Selective Hydroarylation of 1,3-Diynes Using a Dimeric Manganese Catalyst: Modular Synthesis of Z-Enynes

The transition-metal-catalyzed selective hydroarylation of unsymmetrical alkynes represents the state-of-art in organic chemistry, and still mainly relies on the use of precious late-transition-metal catalysts. Reported herein is an unprecedented Mn^I -catalyzed hydroarylation of unsymmetrical 1,3-diyne alcohols with commercially available arylboronic acids with predictive selectivity. This method addresses the challenges in regio-, stereo-, and chemoselectivity. It offers a general, convenient and practical strategy for the modular synthesis of multisubstituted Z-configurated conjugated enynes. This protocol is distinguished by its operational simplicity, complete selectivity, excellent functional-group compatibility, and gram-scale potential. A dimeric Mn^I species, Mn₂ (CO)₈ Br₂ , was proven to be a much more efficient catalyst precursor than Mn(CO)₅ Br.