Asymmetric Synthesis of Acyclic 1,3-Amino Alcohols by Reduction of <i>N</i>-Sulfinyl β-Amino Ketones. Formal Synthesis of (−)-Pinidinol and (+)- Epipinidinol
作者:Franklin A. Davis、Paul M. Gaspari、Brad M. Nolt、Peng Xu
DOI:10.1021/jo801653c
日期:2008.12.19
Stereoselective reduction of acyclic N-sulfinyl beta-amino ketones with (LiEt(3)BH) and Li(t-BuO)(3)AlH, respectively, gave anti- and syn-1,3-amino alcohols with excellent selectivity. A formal asymmetric synthesis of the hydroxy piperidine alkaloids (-)-pinidinol and (+)-epipinidinol from a common N-sulfinyl beta-amino ketone ketal precursor was developed. The pinidinol piperidine ring was formed
Treatment of N-tosylaldimines with acetophenone at room temperature in the presence of Bf(3)center dot OEt2 as a catalyst furnished the corresponding N-tosyl beta-amino ketones in high yields (77-86%) within 6-9 h. Subsequent reduction and cyclization of these compounds afforded 2,4-disubstituted N-tosylazetidines, comprising a three-step, high-yielding synthesis starting from aldimines.
POWELL B. F.; REICHENTHAL J.; OVERBERGER C. G.; ANSELME J.-P., J. HETEROCYCL. CHEM., 1980, 17, NO 2, 219-224
作者:POWELL B. F.、 REICHENTHAL J.、 OVERBERGER C. G.、 ANSELME J.-P.