Synthesis 2004(5): 796-800  
DOI: 10.1055/s-2003-44368
PSP
© Georg Thieme Verlag Stuttgart · New York

Simple Large-Scale Preparation of 3,3-Disubstituted Cyclopropenes: Easy Access to Stereodefined Cyclopropylmetals via Transition Metal-Catalyzed Hydrometalation

Michael Rubin, Vladimir Gevorgyan*
Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, IL 60607-7061, USA
Fax: +1(312)3550836; e-Mail: vlad@uic.edu;
Further Information

Publication History

Received 15 November 2003
Publication Date:
09 December 2003 (online)

Abstract

3,3-Disubstituted cyclopropenes have been readily prepared in a multigram scale via two different methods: (1) dehydrohalogenation of bromocyclopropanes, and (2) Rh-catalyzed addition of carbenoids to trimethylsilylacetylene followed by desilylation. Highly diastereoselective­ Pd-catalyzed hydrostannation and highly enantioselective Rh-catalyzed hydroboration of 3,3-disubstituted cyclopro­penes afforded useful cyclopropylmetal building blocks in high yields.

11

See Refs. [5a] [b] and references cited therein.

16

For transition metal-catalyzed 3-acyl- or 3-alkoxy-carbonylcyclopropene to furan isomerizations, see refs. [3c] [d] .