Stereoselective formal [3 + 3] cycloaddition approach to cis-1-azadecalins and synthesis of (-)-4a,8a-diepi-pumiliotoxin C. evidence for the first highly stereoselective 6pi-electron electrocyclic ring closures of 1-azatrienes.
Evidence is described here to support that a highly stereoselective 6pi-electron electrocyclic ring closure of 1-azatrienes is a key step in formal [3 + 3] cycloaddition or annulation reactions of chiral vinylogous amides with alpha,beta-unsaturated iminium salts. This would represent the first highly stereoselective 6pi-electron electrocyclic ring closure of 1-azatrienes. We have also unambiguously demonstrated that these specific ring closures are reversible, leading to the major diastereomer that is also thermodynamically more stable, and that a rotation preference likely also plays a role. A synthetic application is illustrated here to stereoselectively transform the resulting dihydropyridines to cis-1-azadecalins with unique anti relative stereochemistry at C2 and C2a, leading to synthesis of epi isomers of (-)-pumiliotoxin C.
Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Heather M
HM
Sklenicka
Richard P
RP
Hsung
Michael J
MJ
McLaughlin
Lin-Li
LL
Wei
Aleksey I
AI
Gerasyuto
William B
WB
Brennessel
D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry; D000664:Amphibian Venoms / Q000138:chemical synthesis* / Q000737:chemistry; D001372:Aza Compounds / Q000138:chemical synthesis / Q000737:chemistry; D003500:Cyclization; D009281:Naphthalenes / Q000138:chemical synthesis* / Q000737:chemistry; D011804:Quinolines; D013237:Stereoisomerism
D000470:Alkaloids; D000475:Alkenes; D000664:Amphibian Venoms; D001372:Aza Compounds; D009281:Naphthalenes; D011804:Quinolines; C011093:pumiliotoxin C; C007229:decalin