Intramolecular 4+3 cycloadditions. Allylic sulfones as precursors to vinylthionium ions
作者:Michael Harmata、Mehmet Kahraman
DOI:10.1016/s0040-4039(98)00582-6
日期:1998.5
Treatment of a THF solution of(E)-3 with n-BuLi followed by quenching with an electrophile generally results in regioselective alkylation alpha to the sulfone with the alkene possessing (E) stereochemistry in the major product. High selectivity for the (E) alkylation product can be achieved in the presence of small amounts of HMPA. When those (E) alkylation products possessing a diene moiety in the side chain are treated with Lewis acids, 4+3 cycloaddition products are formed in good to excellent yields. (C) 1998 Elsevier Science Ltd. All rights reserved.