Diastereoselective allylation of α-ketoamides bearing camphor N-tosylpyrazolidinone auxiliary:: Efficient synthesis of highly optically active two stereoisomers
allylation;
reversal of stereoselectivity;
chiral auxiliary;
D O I:
10.1016/j.tet.2005.10.042
中图分类号:
O62 [有机化学];
学科分类号:
070303 ;
081704 ;
摘要:
Complementary allylation conditions were developed for the synthesis of both diastereomers of tertiary homoallylic alcohols. Treatment of camphor N-tosylpyrazolidinone derived alpha-ketoamides with allyltributylstannane afforded both the individual homoallylic alcohols in high optical purity (up to 98% de) when the reaction was carried out in the presence of Sn(OTf)(2) and PdCl2, respectively. The stereochemical outcome and reversal of stereoselectivity in the reaction are proposed based on C-13 NMR and FTIR studies. (c) 2005 Elsevier Ltd. All rights reserved.