A Convergent Strategy for the Asymmetric Synthesis of Enantiomerically Pure Bicyclic Compounds by Using a Silicon-Directed Cycloaddition Reaction: The Synthesis of Enantiomerically Pure Bicyclo

Angew Chem Int Ed Engl. 1999 Sep;38(18):2728-2730. doi: 10.1002/(sici)1521-3773(19990917)38:18<2728::aid-anie2728>3.0.co;2-0.

Abstract

An asymmetric allylmetalation followed by a silicon-stereodirected cycloaddition gives enantiomerically pure bicyclic compounds. The synthesis of enantiopure 1 (see scheme) in a yield of 65-74 %, 93 % ee, and >98 % de provides an illustration of the efficacy of the method. The preferential formation of 1 rather than its diastereoisomer (32:1), during the cycloaddition step, matches the result predicted by RHF and density functional theory studies.