An efficient [4 + 2 + 1] entry to seven-membered rings.
A new nickel-catalyzed procedure for the [4 + 2 + 1] cycloaddition of trimethylsilyl diazomethane with alkynes tethered to dienes has been developed. A broad range of unsaturated substrates participate in the sequence, and stereoselectivities are generally excellent. Three possible mechanisms are proposed, and each involves the generation of a transient nickel carbene species.
Ni
Yike
Y
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
Montgomery
John
J
D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis; D002384:Catalysis; D003500:Cyclization; D009532:Nickel
D000475:Alkenes; D000480:Alkynes; D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D009532:Nickel