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Stereo‐ and Regioselective Alkyne Hydrometallation with Gold(III) Hydrides
Author(s) -
Pintus Anna,
Rocchigiani Luca,
FernandezCestau Julio,
Budzelaar Peter H. M.,
Bochmann Manfred
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201607522
Subject(s) - alkyne , regioselectivity , chemistry , radical , stereospecificity , hydride , radical initiator , reaction mechanism , medicinal chemistry , stereochemistry , photochemistry , metal , catalysis , organic chemistry , polymerization , polymer
The hydroauration of internal and terminal alkynes by gold(III) hydride complexes [(C^N^C)AuH] was found to be mediated by radicals and proceeds by an unexpected binuclear outer‐sphere mechanism to cleanly form trans ‐insertion products. Radical precursors such as azobisisobutyronitrile lead to a drastic rate enhancement. DFT calculations support the proposed radical mechanism, with very low activation barriers, and rule out mononuclear mechanistic alternatives. These alkyne hydroaurations are highly regio‐ and stereospecific for the formation of Z ‐vinyl isomers, with Z / E ratios of >99:1 in most cases.