All Related Questions of Chiral

Q: Predict the products for each of the following reactions. Note:

Predict the products for each of the following reactions. Note: in some cases, the reaction produces a new chiral center, while in other cases, no new chiral center is formed.

Q: Compound A and compound B both have the molecular formula C6H12.

Compound A and compound B both have the molecular formula C6H12. Both compounds produce epoxides when treated with a peroxy acid (RCO3H). a. The epoxide resulting from compound A was treated with aqu...

Q: Predict the product(s) for each of the following reactions

Predict the product(s) for each of the following reactions. In each case, make sure to consider the number of chiral centers being formed.

Q: Compound A has the molecular formula C5H10. Hydroborationoxidation of compound A

Compound A has the molecular formula C5H10. Hydroborationoxidation of compound A produces an alcohol with no chiral centers. Draw two possible structures for compound A.

Q: (+)-Citronellal is the main compound responsible for the lemon scent of

(+)-Citronellal is the main compound responsible for the lemon scent of citronella oil. In addition to its well-known insect repellant properties, it also has some antifungal properties. (+)-Citronell...

Q: Compound A is an alkyne that reacts with two equivalents of H2

Compound A is an alkyne that reacts with two equivalents of H2 in the presence of Pd to give 2,4,6-trimethyloctane. a. Draw the structure of compound A. b. How many chiral centers are present in com...

Q: Carbohydrates such as the glucose derivative shown below can serve as useful

Carbohydrates such as the glucose derivative shown below can serve as useful chiral starting materials for biopolymers and natural product synthesis. Radical bromination of this compound occurs at C1...

Q: Predict the products for each reaction. In each case, be

Predict the products for each reaction. In each case, be sure to consider whether a chiral center is being generated, and then draw all expected stereoisomers.

Q: The hydronaphthacene ring system consists of five fused six-membered rings

The hydronaphthacene ring system consists of five fused six-membered rings, as shown below in compounds 3 and 4. One method for construction of this ring system involves treatment of compound 1 with a...

Q: Compound X has the molecular formula C5H10. In the presence of

Compound X has the molecular formula C5H10. In the presence of a metal catalyst, compound X reacts with one equivalent of molecular hydrogen to yield 2-methylbutane. a. Suggest three possible structu...

Q: Compound A has the molecular formula C5H11Br. When compound A is

Compound A has the molecular formula C5H11Br. When compound A is treated with bromine in the presence of UV light, the major product is 2,2-dibromopentane. Treatment of compound A with NaSH (a strong...

Q: A small class of natural products, called α,α-

A small class of natural products, called α,α-disubstituted α-amino acids (Chapter 25), have been the targets of several synthetic techniques, because these c...

Q: The sequence below shows an enantioselective synthesis of a diol that is

The sequence below shows an enantioselective synthesis of a diol that is achieved via two sequential reactions: 1. asymmetric biooxidation (in the presence of enzymes, nature’s cata...

Q: We saw a general rule that the two protons of a CH2

We saw a general rule that the two protons of a CH2 group will be chemically equivalent if there are no chiral centers in the compound. An example of an exception is 3-bromopentane. This compound does...

Q: Diisopinocampheylborane (Ipc2BH) is a chiral organoborane, readily employed for

Diisopinocampheylborane (Ipc2BH) is a chiral organoborane, readily employed for the production of many asymmetric products used in total synthesis. It is a crystalline material that can be prepared as...

Q: When the following chiral epoxide is treated with aqueous sodium hydroxide,

When the following chiral epoxide is treated with aqueous sodium hydroxide, only one product is obtained, and that product is achiral. Draw the product and explain why only one product is formed.

Q: Guggul is an herbal extract from the resin of the mukul myrrh

Guggul is an herbal extract from the resin of the mukul myrrh tree, and it shows potential for treating high cholesterol. In a recent synthesis of (+)-myrrhanol A (a compound present in guggul), compo...

Q: Reboxetine mesylate is used in the treatment of depression and is currently

Reboxetine mesylate is used in the treatment of depression and is currently marketed as the racemate. The (S,S)-enantiomer of reboxetine is being evaluated for the treatment of neuropathic pain. The f...

Q: Assign a name for each of the following compounds. Be sure

Assign a name for each of the following compounds. Be sure to assign the configuration of each chiral center and indicate the configuration(s) at the beginning of the name.

Q: Identify all chiral centers in each of the following compounds:

Identify all chiral centers in each of the following compounds:

Q: Each of the following compounds possesses carbon atoms that are chiral centers

Each of the following compounds possesses carbon atoms that are chiral centers. Locate each of these chiral centers and identify the configuration of each one:

Q: In Chapter 24, we will see that amino acids (like

In Chapter 24, we will see that amino acids (like the ones shown below) can be linked together to give short chains, called peptides, or longer chains (≈50–2000 ami...

Q: A racemic mixture with the constitution shown below was isolated from the

A racemic mixture with the constitution shown below was isolated from the Maytenus apurimacensis plant that is used in South American folk medicine. In an effort to find another source of these compou...

Q: Identify the configuration of the chiral center in each of the following

Identify the configuration of the chiral center in each of the following compounds:

Q: Protease inhibitors are a class of anti-viral drugs that have

Protease inhibitors are a class of anti-viral drugs that have had success in treating HIV/AIDS. The following molecules were synthesized as potential HIV protease inhibitors. Compound 1 was found to b...

Q: Determine whether each of the following allenes is chiral or achiral:

Determine whether each of the following allenes is chiral or achiral:

Q: Atorvastatin is sold under the trade name Lipitor and is used for

Atorvastatin is sold under the trade name Lipitor and is used for lowering cholesterol. Annual global sales of this compound exceed $13 billion. Assign a configuration to each chiral center in atorvas...

Q: Paclitaxel (marketed under the trade name Taxol) is found in

Paclitaxel (marketed under the trade name Taxol) is found in the bark of the Pacific yew tree, Taxus brevifolia, and is used in the treatment of cancer: a. Draw the enantiomer of paclitaxel. b. How...

Q: Assign the configuration of the chiral center in the following compound:

Assign the configuration of the chiral center in the following compound:

Q: Carbon is not the only element that can function as a chiral

Carbon is not the only element that can function as a chiral center. In Problem 5.6 we saw an example in which a phosphorus atom is a chiral center. In such a case, the lone pair is always assigned th...

Q: Identify the configuration of each chiral center in the following compounds:

Identify the configuration of each chiral center in the following compounds:

Q: Determine whether each statement is true or false: a.

Determine whether each statement is true or false: a. A racemic mixture of enantiomers is optically inactive. b. A meso compound will have exactly one nonsuperimposable mirror image. c. Rotating th...

Q: Determine the configuration for every chiral center in each of the following

Determine the configuration for every chiral center in each of the following compounds:

Q: Each of 10 stereoisomeric sugar derivatives can be prepared via a multiple

Each of 10 stereoisomeric sugar derivatives can be prepared via a multiple-step synthesis starting from either glucuronolactone 1D or its enantiomer 1L. Depending on the specific series of reactions u...

Q: Strychnine (6), a notorious poison isolated from the strychnos genus

Strychnine (6), a notorious poison isolated from the strychnos genus, is commonly used as a pesticide in the treatment of rodent infestations. The sophisticated structure of strychnine, first elucidat...

Q: Identify whether each of the following compounds is chiral or achiral:

Identify whether each of the following compounds is chiral or achiral:

Q: There are many examples of carbocation rearrangements that cannot be classified as

There are many examples of carbocation rearrangements that cannot be classified as a methyl shift or hydride shift. For example, consider the following rearrangement that was employed in the synthesis...

Q: The following compound, whose central ring is referred to as a

The following compound, whose central ring is referred to as a 1,2,4-trioxane, is an anticancer agent that demonstrates activity against canine osteosarcoma. Assign the configuration of each chiral ce...

Q: Coibacin B is a natural product that exhibits potent antiinflammatory activity and

Coibacin B is a natural product that exhibits potent antiinflammatory activity and potential activity in the treatment of leishmaniasis, a disease caused by certain parasites: a. Assign the configura...

Q: Over 100 cannabinoid compounds, including the one shown below, have

Over 100 cannabinoid compounds, including the one shown below, have been isolated from the marijuana plant in order to explore the plant’s medicinal properties. Identify the chiral c...

Q: Chiral catalysts can be designed to favor the formation of a single

Chiral catalysts can be designed to favor the formation of a single enantiomer in reactions where a new chiral center is formed. Recently, a novel type of chiral copper catalyst was developed that is...

Q: In 2010 the structure of the compound (+)-trigonoliimine A (isolated

In 2010 the structure of the compound (+)-trigonoliimine A (isolated from the leaves of a plant in the Yunnan province of China) was reported as shown below. In 2011, a synthesis of the reported struc...

Q: Consider the reaction below, which involves both a dehydrogenation (removal

Consider the reaction below, which involves both a dehydrogenation (removal of two neighboring hydrogen atoms) and a Diels-Alder reaction (which we will learn about in Chapter 16). Utilizing a special...

Q: (R)-(−)-Carvone is responsible for the characteristic minty odor and

(R)-(−)-Carvone is responsible for the characteristic minty odor and flavor of spearmint oil, and it can also serve as a useful chiral starting material for organic synthesis. A carb...

Q: Consider the following SN2 reaction: / a.

Consider the following SN2 reaction: a. Assign the configuration of the chiral center in the substrate. b. Assign the configuration of the chiral center in the product. c. Does this SN2 process proc...

Q: Pladienolide B is a macrocyclic (large ring) natural product isolated

Pladienolide B is a macrocyclic (large ring) natural product isolated from an engineered strain of the bacterium Streptomyces platensis. An enantioselective, 31-step synthesis of it was reported18 in...

Q: The following synthetic step was utilized as part of a recent synthesis

The following synthetic step was utilized as part of a recent synthesis of the polycyclic natural product haouamine B. In this reaction, the function of the first reagent (triflic anhydride) is to act...

Q: When conducted in a chiral environment (for example, by using

When conducted in a chiral environment (for example, by using a chiral catalyst or adding a chiral auxiliary), an asymmetric aldol reaction can occur that favors the production of a single stereoisome...

Q: Endiandric acids are a class of natural products isolated from the Australian

Endiandric acids are a class of natural products isolated from the Australian plant Endiandra introrsa. Natural products containing chiral centers are generally found in nature as a single enantiomeri...

Q: As shown, compound 1 can be transformed to compound 2,

As shown, compound 1 can be transformed to compound 2, which undergoes a thio-Claisen rearrangement (similar to a Claisen rearrangement, but with sulfur instead of oxygen) to give compound ...

Q: Chiral amines are used to catalyze a host of different enantioselective transformations

Chiral amines are used to catalyze a host of different enantioselective transformations. For instance, proline (explored further in Chapter 25) is a naturally occurring, chiral amino acid that can be...

Q: The mechanism for acetal hydrolysis has been heavily investigated. In one

The mechanism for acetal hydrolysis has been heavily investigated. In one study, which explored rates as well as stereochemical aspects, compound 1 was treated with aqueous acid to afford compound 2....

Q: Provide a systematic (IUPAC) name for the compound below.

Provide a systematic (IUPAC) name for the compound below. Be careful: This compound has two chiral centers (can you find them?).

Q: Draw all constitutionally isomeric aldehydes with the molecular formula C5H10O and provide

Draw all constitutionally isomeric aldehydes with the molecular formula C5H10O and provide a systematic (IUPAC) name for each isomer. Which of these isomers possesses a chiral center?

Q: The following reaction utilizes a Michael addition, followed by a Claisen

The following reaction utilizes a Michael addition, followed by a Claisen-type reaction to make chiral diketoester 3 as part of the total synthesis of dynemycin A, a natural product with promising ant...

Q: Draw the structures of eight different carboxylic acids with the molecular formula

Draw the structures of eight different carboxylic acids with the molecular formula C6H12O2. Then, provide a systematic name for each compound and identify which three isomers exhibit chiral centers.

Q: Identify the number of chiral centers in each of the following structures

Identify the number of chiral centers in each of the following structures:

Q: Tertiary amines with three different alkyl groups are chiral but cannot be

Tertiary amines with three different alkyl groups are chiral but cannot be resolved because pyramidal inversion causes racemization at room temperature. Nevertheless, chiral aziridines can be resolved...

Q: In a study exploring the utility of olefin metathesis reactions, the

In a study exploring the utility of olefin metathesis reactions, the following triene was prepared and subjected to a Grubbs catalyst. The triene underwent a tandem ring-opening/ring-closing reaction...

Q: The following compound will undergo an intramolecular Heck reaction to give a

The following compound will undergo an intramolecular Heck reaction to give a single product with two chiral centers. This process is observed to occur diastereoselectively (a new chiral center is for...

Q: Compound A is an amine that does not possess a chiral center

Compound A is an amine that does not possess a chiral center. Compound A was treated with excess methyl iodide and then heated in the presence of aqueous silver oxide to produce an alkene. The alkene...

Q: Determine whether each of the following carbohydrates is a D sugar or

Determine whether each of the following carbohydrates is a D sugar or an L sugar and assign a configuration for each chiral center. After assigning the configuration for all of the chiral centers, do...

Q: D-allose is an aldohexose in which all four chiral centers

D-allose is an aldohexose in which all four chiral centers have the R configuration. Draw a Fischer projection of each of the following compounds: a. D-Allose b. L-Allose

Q: Assign the configuration of each chiral center in the following compounds:

Assign the configuration of each chiral center in the following compounds:

Q: When D-glucose is treated with an aqueous bromine solution (

When D-glucose is treated with an aqueous bromine solution (buffered to a pH of 6), an aldonic acid is formed called D-gluconic acid. Treatment of D-gluconic acid with an acid catalyst produces a lact...

Q: Although most naturally occurring proteins are made up only of L amino

Although most naturally occurring proteins are made up only of L amino acids, proteins isolated from bacteria will sometimes contain d amino acids. Draw Fischer projections for D-alanine and D-valine....

Q: Explain why it is inappropriate to use a chiral catalyst in the

Explain why it is inappropriate to use a chiral catalyst in the preparation of glycine.

Q: The 20 naturally occurring amino acids (Table 25.1)

The 20 naturally occurring amino acids (Table 25.1) are all L amino acids, and they all have the S configuration, with the exception of glycine (which lacks a chiral center) and cysteine. Naturally oc...

Q: Seventeen of the 20 naturally occurring amino acids exhibit exactly one chiral

Seventeen of the 20 naturally occurring amino acids exhibit exactly one chiral center. Of the remaining three amino acids, glycine has no chiral center, and the other two amino acids each have two chi...

Q: Draw all stereoisomers of L-isoleucine. In each stereoisomer,

Draw all stereoisomers of L-isoleucine. In each stereoisomer, assign the configuration (R or S) of all chiral centers

Q: Draw a chiral triglyceride that contains one palmitic acid residue and two

Draw a chiral triglyceride that contains one palmitic acid residue and two myristic acid residues. Will this compound react with molecular hydrogen in the presence of a catalyst?

Q: Limonene is an optically active compound isolated from the peels of lemons

Limonene is an optically active compound isolated from the peels of lemons and oranges. a. Is limonene a monoterpene or a diterpene? b. Treatment of limonene with excess HBr yields a compound with t...

Q: 2. Label the conformation of the molecule as either cis or

2. Label the conformation of the molecule as either cis or trans 3. Label the following molecules as either chiral or achiral

Q: Does glycine have a chiral carbon? Explain your reasoning.

Does glycine have a chiral carbon? Explain your reasoning.

Q: Draw an aldotetrose. Note each chiral carbon with an asterisk (*).

Draw an aldotetrose. Note each chiral carbon with an asterisk (*).

Q: Erythritol is a four-carbon sugar alcohol and xylitol is a

Erythritol is a four-carbon sugar alcohol and xylitol is a five-carbon sugar alcohol. Like sorbitol and mannitol, they are used as sugar substitutes. Xylitol has the additional benefit of reducing den...

Q: Draw a Fischer Projection formula for each of the following compounds.

Draw a Fischer Projection formula for each of the following compounds. Indicate each of the chiral carbons with an asterisk (*). a. b. c.

Q: What is a chiral carbon atom?

What is a chiral carbon atom?

Q: Define a) Isocratic elution. b) Gradient elution

Define a) Isocratic elution. b) Gradient elution. c) Normal-phase packing. d) Reversed-phase packing. e) Bonded-phase packing f) Chiral chromatography. g) Ion-pair chromatography. h) Eluent-su...