Stereoconvergent palladium-catalyzed carbonylation of both E and Z isomers of a 2-trifloxy-1,3-butadiene.
[reaction: see text] Carbonylation of the illustrated Z-tetrasubstituted enol triflate followed by tandem silyloxy-Cope rearrangement leads to the CP-263, 114 core ring system with the all-carbon quaternary stereocenter intact in 46% yield. Subjection of the corresponding E isomer to the same conditions gives the same product in 56% yield. This observation is explained by a mechanism involving isomerization of a pi-allyl palladium species involving an allenic intermediate.
Bio
M M
MM
Department of Chemistry, Columbia University, New York, New York, 10027, USA.
Leighton
J L
JL
D002070:Butadienes / Q000737:chemistry*; D002384:Catalysis; D008299:Maleic Anhydrides / Q000138:chemical synthesis; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
D002070:Butadienes; C104957:CP 263114; D008299:Maleic Anhydrides; D010165:Palladium