Approach to Phenanthroindolizidine Alkaloids Using Organic Azides with 1-Aryl Allylic Alcohols: Unexpected Tandem Reactions to Indenyl Aziridines via Nazarov Cyclization
摘要:
Organic azide cyclization reactions with 1-aryl allylic alcohols were investigated in a synthetic study of phenanthroindolizidine alkaloids. Unsaturated imines (enimines) were effectively obtained from the allylic alcohol adjacent to electron-rich aromatic rings under thermal reaction conditions. The tandem aziridination-Nazarov reactions to indenyl aziridines were preferred to the acid-mediated enimine formation via Schmidt reaction in the case of 3-aryl diallylic alcohols.
Synthesis of 3-Aryl-Substituted Tetrahydropyran-4-ones and Tetrahydrothiopyran-4-ones
作者:Jens Christoffers、Anna Rosiak
DOI:10.1055/s-2006-941572
日期:2006.6
A series of tetrahydropyran-4-one and tetrahydrothiopyran-4-one derivatives with 3-aryl or 3,6-diaryl substituents were prepared by double conjugate addition of water or H2S to divinyl ketones. These starting materials were accessed in two steps by conversion of lithiated α-bromostyrene derivatives with acrolein or cinnamaldehyde and subsequent oxidation of the divinylalcohols with MnO2.
Synthesis of Tetrahydropyran-4-ones and Thiopyran-4-ones from Donor-Substituted α-Bromostyrene Derivatives
作者:Anna Rosiak、Wolfgang Frey、Jens Christoffers
DOI:10.1002/ejoc.200600372
日期:2006.9
Tetrahydropyran-4-one and tetrahydrothiopyran-4-one derivatives with a 3-aryl substituent were synthesized by double-conjugate addition of water or H2S to divinyl ketones. These starting materials were prepared in two steps by conversion of lithiated α-bromostyrene derivatives with acrolein or cinnamaldehyde and subsequent oxidation of the divinyl alcohols with MnO2. The electron-rich α-bromostyrene
Formal Synthesis of Indolizidine and Quinolizidine Alkaloids from Vinyl Cyclic Carbonates
作者:Àlex Cristòfol、Christian Böhmer、Arjan W. Kleij
DOI:10.1002/chem.201904223
日期:2019.11.27
groups in complex multistep synthetic routes. This study shows that a concise, yet modular synthesis of indolizidine and quinolizidine alkaloids can be developed from vinyl-substituted cyclic carbonate (VCC) intermediates. Through a highly stereoselective palladium-catalyzed allylic alkylation reaction, these alkaloid motifs can be assembled in four synthetic and only two column purification steps. The