Enantiomers chiral auxiliaries, drug synthesis

Sibutramine 144 is the active enantiomer of the drug Meridia (Abbott Laboratories), which is a potent neurotransmitter reuptake inhibitor used for treating central nervous system disorders.Sepracor devised an asymmetric synthesis of the active enantiomer 144 that relies on the use of the oxathiazolidine oxide 137 as a chiral auxiliary. 

Another auxiliary that proved to be useful as a base for enolate alkylations is cis-l-amino-2-indanol 37 developed by researchers at Merck, Sharp, and Dhome. Both enantiomers of the amino alcohol are commercially available in bulk. The alkylation method was elaborated for a synthesis of indinavir, the orally active HIV protease inhibitor that emerged as a major drug for treatment of AIDS. Thus, N-acylated Af,0-acetal 38 was converted into the lithium enolate and subsequently treated with allyl bromide to give the alkene 39 in excellent chemical yield and diastereoselectivity. The conversion into indinavir reveals that the amino alcohol 37 functions both as auxiliary and chiral building block (Scheme 4.8) [26]. 

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