Tandem double intramolecular [4+2]/[3+2] cycloadditions of nitroalkenes: construction of the pentacyclic core structure of daphnilactone B
作者: Scott E. DenmarkRamil Y. BaiazitovSon T. Nguyen
作者单位: 1Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
刊名: Tetrahedron, 2009, Vol.65 (33), pp.6535-6548
来源数据库: Elsevier Journal
DOI: 10.1016/j.tet.2009.05.060
关键词: Tandem cycloadditionNitroalkeneAlkaloid
英文摘要: Abstract(#br)An asymmetric synthesis of the ABCD ring system of daphnilactone B is described. The synthesis features a tandem, double intramolecular, [4+2]/[3+2] cycloaddition of a highly functionalized, enantiomerically enriched nitroalkene to generate a pentacyclic nitroso acetal. The cycloaddition establishes six contiguous stereogenic centers including the critical CD ring junction that bears two quaternary stereogenic centers. Hydrogenolysis of the nitroso acetal followed by amide reduction and cyclization provided the AB rings. The methyl substituent on the A ring was installed in the correct configuration via hydrogenation of an exocyclic olefin in the final step.
全文获取路径: Elsevier  (合作)
影响因子:2.803 (2012)