Addition of Enantioenrichedγ-Oxygenated Allylic Stannanes toN-Acyl Iminium Intermediates: A New Synthesis ofsyn-Amino Alcohol Derivatives

Abstract

An ortho-methoxybenzyl substituent is the key to high diastereoselectivities in a novel synthesis of syn-β-amino alcohols from N-benzyl-N-carbethoxyiminium salts and γ-oxygenated allylic stannanes (the reaction is promoted by the Lewis acid BF3⋅OEt2; see scheme). Enantioselectivites of over 95 % and syn:anti ratios of greater than 95:5 were achieved. Ar=o-MeOC6H4, MOM=methoxymethyl.