probed by the examination of the behavior of vinylcyclobutanols as terminators in cyclization reactions. The substrates were readily available by the addition of vinyllithium reagents bearing acetals as cyclization initiators to cyclobutanone. Bronsted and Lewis acids both promoted cyclization in contrast to vinylcyclopropanolterminators for which Bronsted acids failed. The products are spirocycles consisting
Small rings through large templates: A two‐point binding of the substrate radicals to cationic titanocene templates is essential for the success of otherwise impossible 4‐exo cyclizations (see scheme; Bn=benzyl). The cyclobutanes are obtained in high stereoselectivity and can be additionally functionalized in a straightforward manner.
Studies toward the total synthesis of sarsolilide A: preparation of the proper precursor for the macrocyclization
作者:Jiazhong Zhang、Xingxiang Xu
DOI:10.1016/s0040-4039(98)01409-9
日期:1998.9
A strategically functionalized chiral cyclopentane, as a proper precursor for the synthesis of Sarsolilide A, has been synthesized with complete stereochemical control. (C) 1998 Elsevier Science Ltd. All rights reserved.
BOECKMAN, ROBERT K. (JR);OCONNOR, KENNETH J., TETRAHEDRON LETT., 30,(1989) N5, C. 3271-3274