Carbon-carbon bond formation and pyrrole synthesis via the [3,3] sigmatropic rearrangement of O-vinyl oxime ethers.
A new method for the synthesis of 2,4- and 2,3,4-substituted pyrroles in two or three steps from commercially available ketones and allyl hydroxylamine is described. An iridium-catalyzed isomerization reaction has been developed to convert O-allyl oximes to O-vinyl oximes, which undergo a facile [3,3] rearrangement to form 1,4-imino aldehyde Paal-Knorr intermediates that cyclize to afford the corresponding pyrroles. Optimization and examples of the isomerization and pyrrole formation are discussed.
Wang
Heng-Yen
HY
Department of Chemistry, University of Illinois, Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.
Mueller
Daniel S
DS
Sachwani
Rachna M
RM
Londino
Hannah N
HN
Anderson
Laura L
LL
D002244:Carbon / Q000737:chemistry*; D003500:Cyclization; D004987:Ethers / Q000737:chemistry*; D015394:Molecular Structure; D010091:Oximes / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D004987:Ethers; D010091:Oximes; D011758:Pyrroles; D002244:Carbon