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DOI: 10.1055/s-0033-1340451
Ring Opening of Azabicyclic Alkenes Co-Catalyzed by Palladium and Copper
Palladium/Copper Complexes Co-Catalyzed Highly Enantioselective Ring Opening Reaction of Azabenzonorbornadienes with Terminal Alkynes.
Adv. Synth. Catal. 2013;
355: 2827-2832
Publication History
Publication Date:
13 December 2013 (online)
Significance
The ring opening of strained meso-heterobicyclic alkenes with different nucleophiles serves as a useful strategy for setting multiple stereocenters in a single transformation. Previous methods for this particular ring opening were limited to the use of bulky terminal acetylenes. Here, the authors report the development of a palladium and copper co-catalyzed system that exhibits broad substrate scope.
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Comment
The authors propose that the copper(I) catalyst plays two distinct roles in the mechanism: (1) Copper facilitates transmetalation of the acetylene to palladium via the copper acetylide; (2) Copper behaves as a Lewis acid to activate the azabicyclic alkene. In addition to demonstrating wide functional group tolerance, the yields and enantioselectivities observed are excellent across the series of substrates tested.
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