Titanium-Mediated Cyclopropanation of Esters with Grignard Reagents

Significance

The authors report an optimized protocol for the preparation of cis-1,2-dialkylcyclopropanols. While cis and trans cyclopropanols of type 2a,b are chromatographically separable, the previous procedure gave significant amounts of secondary alcohol of type 3 which could not be separated from the cis product. The authors found that by addition of MeMgI, the yields of cyclopropanols could be increased and the production of secondary alcohol suppressed.