Configurational Stability of a Cyclopropyl Grignard Reagent Containing a Metalated 2-Hydroxymethyl Group

Article abstract of DOI:10.1021/jo00170a027

Mixtures of cis- and trans-2-bromo-3-(hydroxymethyl)-1,1-dimethylcyclopropane were treated with methylmagnesium bromide to metalate the hydroxyl groups and then with magnesium to form metalated Grignard reagents.The compositions of products obtained upon hydrolysis with D2O indicated that the metalated Grignard reagents in refluxing diethyl ether did not undergo significant cis-trans isomerization.This work provides an example of the configurational stability of a cyclopropyl Grignard reagent with a secondary rather than a tertiary α-carbon.Because of these resultswith cyclopropyl Grignard reagents containing a metalated hydroxyl group, prior observations on additions of allylic Grignard reagents to 3-(hydroxymethyl)cyclopropenes only of products resulting from a cis relationship of magnesium and hydroxymethyl must be due to the stereochemistry of the addition process rather than to a subsequent isomerization.