Question

Show the structural formula of the predominant product or products formed when (R)-butan-2-ol is treated with each of the following:

a.) PCC (pyridinium chlorochromate)

b.) K2Cr2O7

c.) 1) NaH and then 2) 1-bromobutane

d.) SOCl2

e.) PBr3

Answer 1

A) Butanone

B) Butanone

C) Sec-butyl Butyl Ether

D) (S)-2-Chloro-Butane

E) (S)-2-Bromo-Butane

Step-by-step explanation:

A) and B) Oxidation of secondaries alcohols gives the corresponding ketone, even if it is a weak oxydation agent like PCC.

C) In the first step the strong base (NaH) attacks the hydroxyl group deprotonating it resulting in the formation of H2 (gas) and an alcoxide. Later, in the second step the alcoxide attacks via SN2 the alkyl halide given an ether.

D) E) Thionyl chloride and Phosphorus tribromide are useful agents to substitute an hydroxyl group to the corresponding halide.