N -heterocyclic carbene-mediated formal [3+3] annulation of isatin-derived α, β-unsaturated acids: Access to functionalized 3,4′-spirooxindole δ -lactones
作者:Weiguo Zhang、Junyu Xu、Jing Cao、Chao Fang、Jindong Zhu、Tao Lu、Ding Du
DOI:10.1016/j.tet.2017.04.055
日期:2017.6
acids 2 for the generation of isatin-derived α,β-unsaturated acyl azoliums II was described. The acyl azoliums II were successfully applied to undergo a formal [3 + 3] annulation with 1,3-dicarbonyl compounds to access functionalized 3,4′-spirooxindole δ-lactones 4. A scale-up synthesis and an enantioselective variant of this protocol were also investigated. The stable and easily prepared acids 2 may
Catalytic Enantioselective Desymmetrisation as a Tool for the Synthesis of Hodgkinsine and Hodgkinsine B
作者:Robert H. Snell、Matthew J. Durbin、Robert L. Woodward、Michael C. Willis
DOI:10.1002/chem.201203150
日期:2012.12.21
Two palladium‐catalysed amination protocols are deployed in the desymmetrisation of the complex dimeric alkaloid meso‐chimonanthine. The power of these transformations is showcased in an efficient formal and total synthesis of the natural products hodgkinsine and hodgkinsine B, respectively.