Zhu JL, Wu ST, Shie JY. Access to functionalized bicyclo[4,3,0]nonenes via palladium-catalyzed oxidative cyclization of 2-allylcyclohexyl oximes.
J Org Chem 2014;
79:3623-33. [PMID:
24678644 DOI:
10.1021/jo5005422]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new palladium-catalyzed oxidative cyclization process leading to the functionalized bicyclo[4,3,0]nonenes is serendipitously discovered during attempts to form aza-heterocycle by the amino-Heck reaction of trans-2-vinylclohexyl phosphinyloxime. Under the influence of Pd(dba)2/Et3N/1:1 N2-O2 (1:1, v/v) (Method A) or Pd(OAc)2/Et3N/O2 (Method B), the reactions afford the substituted cis-1-hydroxyl-8-formyl-bicyclo[4,3,0]non-8(9)-enes or bicycle[4,3,0]non-1(9)-en-8-ones in varying yields with the incorporation of molecular oxygen into the structures. The 5,6-bicyclic scaffold of these products is presumably derived from tandem double intramolecular cyclization followed by the ring-opening of an aza-palladium(II) tricyclic intermediate.
Collapse