Studies on the diastereoselective allylation of aldehydes with enantiopure 2-sulfinylallyl building blocks
摘要:
A comparative study on the allylation of aldehydes with enantiopure (S-S)-2-(p-tolylsulfonyl)-prop-2-en-1-ol (S-S)-1a and the corresponding chloride (S-S)-1b under two different reaction systems is reported. In general, better yields were obtained from chloride (S-S)-1b, whereas higher diastereoinduction was observed from alcohol (S-S)-1a. The sense of diastereoinduction is the same in both systems and the stereochemistry of the major diastereomer has been determined. Moreover, the configurational stability of the sulfoxide group on the resulting sulfinyl homoallylic alcohols 3 has been proven in each reaction system. which demonstrates the efficiency of the sulfoxide group as chiral auxiliary in these allylation processes. Finally. as an example of the synthetic potential of the resulting adducts, a total synthesis of natural enantioenriched (S)-nicotine from sulfinylalcohol 3h is reported, (C) 2001 Elsevier Science Ltd. All rights reserved.
An optimized procedure for the diastereoselectiveallylation under aqueous Barbier conditions of a series of alpha-amino aldehydes with our new chiral building block (S(s))-3-chloro-2-(p-tolylsulfinyl)-1-propene [(S(s))-1a] to afford enantiomerically pure sulfinylamino alcohols in good yields and diastereoselectivites is reported. High levels of diastereoinduction can be achieved from alpha-amino aldehydes