Yttrium-Mediated Conversion of Vinyl Grignard Reagent to a 1,2-Dimetalated Ethane and Its Synthetic Application

Abstract

A new 1,2-dimetalated ethane was generated from a vinyl Grignard reagent in the presence of yttrium(III) chloride, sodium cyclopentadienide, and diisobutylaluminum hydride (Dibal). This reagent enables the regio- and stereoselective (metaloethyl)metalation of acetylenes to produce ethylated alkenes after hydrolysis. In addition to simple hydrolysis, further carbon−carbon bond formation or functionalization at the metaloethyl group is possible, demonstrating that the yttrium-based 1,2-dimetalated ethane works as a conjunctive reagent. In addition, the reactive dicarbanionic character of this reagent effects one-pot synthesis of cyclopronanols from esters via consecutive double carbonyl addition.