Interpretation:
The structures for compounds A–J showing stereochemistry in a given sequence are to be written and the stereochemical relationship between (A and C) and (H and J) are to be determined.
Concept introduction:
Electrophiles are electron deficient species that have positive or partially positive charge. Lewis acids are electrophiles that accept electron pair.
Nucleophiles are electron rich species that have negative or partially negative charge. Lewis bases are nucleophiles that donate electron pair.
Substitution reaction: A reaction in which one of the hydrogen atoms of a hydrocarbon or a
Nucleophilic substitution reaction is a reaction in which an electron rich nucleophile attacks the positive or partial positive charge of an atom or a group of atoms to replace a leaving group.
The
The
An
The nucleophilic substitutions in which a nucleophile replaces a leaving group are known as
The stability of carbocation:
Enantiomers and diastereomers are two types of stereoisomers. Enantiomers share mirror image relationship and diastereomers are those in which stereochemistry differs at any one of the chiral centers.
Reaction of alkene with boron hydride followed by treatment with hydrogen peroxide, results in cis addition of hydrogen and hydroxyl groups around the double bond.
Reaction of alcohol with tosyl or mesyl chloride forms tosylates or mesylates, which retains the stereochemistry as the reaction is ester formation and does not involve the chiral carbon.
Tosylates or mesylates can undergo nucleophilic substitution with halides, hydroxides, and acetylides resulting in formation of products with inversion of configuration as the attack of nucleophile occurs at the back side.
Epichlorohydrin is a compound which contains epoxide and chloro substitution alkyl chain. It is formed when ring closure occurs between the hydroxyl and halogen of adjacent carbon atoms.
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Organic Chemistry
- (a) Draw the products (including stereoisomers) formed when 2methylhex-2-ene is treated with HBr in the presence of peroxides. (b) Draw the products (including stereoisomers) formed when (S)-2,4dimethylhex-2-ene is treated with HBr and peroxides under similar conditions.arrow_forward(a) What product is formed when triene N undergoes thermal electrocyclic ring closure? (b)What product is formed when triene N undergoes photochemical ring closure? (c) Label each process as conrotatory or disrotatory.arrow_forwardGive IUPAC names for the following structures. (If appropriate, specify relative stereochemistry.) (a) (b) S Sarrow_forward
- Kindly answer question c & darrow_forwardAlkenes can be converted to alcohols by hydroboration-oxidation. (a) Draw the structure of the alcohol or alcohols formed in the reaction sequence. Clearly indicate stereochemistry by drawing a wedged bond, a dashed bond and two O Hint in-plane bonds per each chiral carbon. Draw hydrogen atoms that are connected to wedge-and-dash bonds.(b) Characterize the product or products of the reactions. The first step of the reaction, hydroboration, involves addition of BH, to the double bond, with -BH, attached to one carbon and hydrogen Be sure to draw hydrogens on oxygen, where applicable. attached to the other. Consider both Rings the regioselectivity and the Select Draw More Erase stereochemistry of this addition. H Diborane, B,H,, is a source of borane, BH,, and can be used 1. B2H6, interchangeably. Diglyme is a solvent. diglyme 2. H2О2, НО", The product or products of the reaction are characterized as being O S. O racemic. O achiral. O R,S (and/or S,R). O R. O S,S. O R.R. O diastereomers.arrow_forwardThe cis ketone A is isomerized to a trans ketone B with aqueous NaOH. A similar isomerization does not occur with ketone C. (a) Draw the structure of B using a chair cyclohexane. (b) Label the substituents in C as cis or trans, and explain the difference in reactivity.arrow_forward
- Kk.58.arrow_forwardThe cis ketone A is isomerized to a trans ketone B with aqueous NaOH. Asimilar isomerization does not occur with ketone C. (a) Draw thestructure of B using a chair cyclohexane. (b) Label the substituents in Cas cis or trans, and explain the difference in reactivity.arrow_forwardDerive an IUPAC name for the following (cyclo)alkenes. (Do not use cis/trans in your names. Use only the (E)/(Z) designations for double bond stereochemistry. It is not necessary to use italics in writing compound names.) (a) (b) my Xarrow_forward
- Rewrite each of the following stereospecific transforms as a synthetic step in the forward direction, including reagents and any special reaction conditions. (a) (b) OH "CH3 CH3 H (Racemic) (c) OH (d) CN Br (Racemic) Brarrow_forwardQ3. 2-Bromopentane, when treated with alcoholic KOH yields a mixture of three alkenes A, B and C. Identify A, B and C. Which is predominant? Q4 Which statement below about Sn1 reactions is incorrect? (A) SN1 reactions are stepwise and have intermediates. (B) The slow step in a SN1 reaction is formation of the carbocation intermediate. (C) SN1 reactions have first order kinetics which means only the alkyl halide is involved in the rate limiting step. (D) The products of a SN1 reaction will be a pair of enantiomers. (E) An aprotic solvent is best for Sn1 reactions as they tend to help stabilize carbocation intermediates.arrow_forward(a) Give an acceptable name for compound A. (b) Draw the organic products formed when A is treated with each reagent: [1] H3O+; [2] −OH, H2O; [3] CH3CH2CH2MgBr (excess), then H2O; [4] LiAlH4, then H2O.arrow_forward