Photoredox Propargylation of Aldehydes Catalytic in Titanium

J Org Chem. 2021 May 7;86(9):7002-7009. doi: 10.1021/acs.joc.1c00521. Epub 2021 Apr 22.

Abstract

A practical and effective photoredox propargylation of aldehydes promoted by 10 mol % of [Cp2TiCl2] is presented. No stoichiometric metals or scavengers are used for the process. A catalytic amount of the cheap and simply prepared organic dye 3DPAFIPN is used as the reductant for titanium. The reaction displayed a broad scope, and no traces of allenyl isomers were detected for simple propargyl bromide, whereas mixtures of propargyl and allenyl isomers were observed for substituted propargyl bromides.