La(CH2C6H4NMe2-o)3-catalyzed reduction of esters to alcohols with pinacolborane

Abstract

Catalytic reduction of esters is a favourable synthetic strategy to obtain the corresponding alcohols. La(CH₂C₆H₄NMe₂-o)₃, a simple and facilely accessible lanthanide complex, can serve as a highly efficient catalyst for the reduction of esters with pinacolborane (HBpin), selectively affording alcohols in good yields under mild conditions. This protocol exhibits good tolerance for many functional groups such as CC double bond, nitro, halogen, furyl, and thienyl groups. A lanthanum hydride species like [La]–H·HBpin is supposed to play a crucial role in promoting the interaction of esters with HBpin.