Chapter 6, Stereospecific and stereoselective reactions Video Solutions, Organic Stereochemistry

Problem 1

(a) How many diastereomers are there of 1,2,3,4,5,6-hexachlorocyclohexane? (b) Which, if any, are chiral? (c) Identify the diastereomer which is $-25,000$ slower in E2 reactions than the others.

Lainey Roebuck

Numerade Educator

04:09

Problem 2

Why is $-\mathrm{CH}_3$ effectively larger than $-\mathrm{CD}_3$ in many reactions (see, e.g., Horeau's Rule, p. 82)?

Lashan De Silva

University of Houston

02:19

Devise molecules and reactions such that (i) a reaction with inversion at a chiral centre does not change the descriptor $R$ for that centre, and (ii) a reaction with retention at a chiral centre changes the descriptor from $R$ to $S$.

Ly Tran

Numerade Educator

03:29

Problem 4

Identify the diastereomers of the products that result from the following stereospecific transformations:
(a)

$$
E-\mathrm{Pr}-\mathrm{CH}=\mathrm{CH}-\mathrm{SiMe}_3 \rightarrow \mathrm{Pr}-\mathrm{CH}=\mathrm{CH}-\mathrm{Pr}
$$

Reagents: (i) $\mathrm{PhCOO}_2 \mathrm{H}$; (ii) $\mathrm{Pr}_2 \mathrm{CuLi}$; (iii) NaH
(b) $\mathrm{Bu}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H} \rightarrow \mathrm{Bu}-\mathrm{CH}=\mathrm{CH}-\left(\mathrm{c}-\mathrm{C}_6 \mathrm{H}_{11}\right)$

Reagents: (i) $\mathrm{HB}\left(\mathrm{c}-\mathrm{C}_6 \mathrm{H}_{11}\right)_2$; (ii) $\mathrm{NaOH} / \mathrm{H}_2 \mathrm{O} / \mathrm{I}_2\left[\mathrm{c}-\mathrm{C}_6 \mathrm{H}_{11}\right.$ = cyclohexyl]
(c) $\mathrm{Bu}-\mathrm{C} \equiv \mathrm{C}-\mathrm{Br} \rightarrow \mathrm{Bu}-\mathrm{CH}=\mathrm{CH}-\left(\mathrm{c}-\mathrm{C}_6 \mathrm{H}_{11}\right)$

Reagents: (i) $\mathrm{HB}\left(\mathrm{c}-\mathrm{C}_6 \mathrm{H}_{11}\right)_2$; (ii) NaOMe ; (iii) $\mathrm{MeCO}_2 \mathrm{H}\left[\mathrm{c}-\mathrm{C}_6 \mathrm{H}_{11}=\right.$ cyclohexyl $]$

Parvati Devi

Numerade Educator

Problem 1

Problem 2

Problem 3

Problem 4