Stereo- and Regioselective Alkyne Hydrometallation with Gold(III) Hydrides.
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.
School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
Anna
0000-0001-6069-9771
A
Pintus
School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
Luca
0000-0002-2679-8407
L
Rocchigiani
School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
Julio
0000-0001-7663-6222
J
Fernandez-Cestau
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada. Peter.Budzelaar@umanitoba.ca.
Peter H M
PH
Budzelaar
School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. m.bochmann@uea.ac.uk.
Manfred
0000-0001-7736-5428
M
Bochmann
alkynes; density functional calculations; gold; insertion; reaction mechanisms