Enantioselective Synthesis of Indolizidines Bearing Quaternary Substituted Stereocenters via Rhodium-Catalyzed [2 + 2 + 2] Cycloaddition of Alkenyl Isocyanates and Terminal Alkynes
作者:Ernest E. Lee、Tomislav Rovis
DOI:10.1021/ol800086s
日期:2008.3.1
An enantioselectivesynthesis of indolizidines bearing quaternary substituted stereocenters by way of a rhodium-catalyzed [2+2+2] cycloaddition of substituted alkenyl isocyanates and terminal alkynes is described. The reaction provides lactam products using aliphatic alkynes, whereas aryl alkynes give rise to vinylogous amide products. Through modification of the phosphoramidite ligand, high levels
Asymmetric routes to azasugars from chiral bicyclic lactams. Synthesis of 1,4-dideoxy-1,4-imino-D-lyxitol; L-deoxymannojirimycin; rhammo-1-deoxynojirimycin and 1-deoxy-6-epicastanospermine
作者:A.I Meyers、Charles J Andres、James E Resek、Charlotte C Woodall、Maureen A McLaughlin、Peter H Lee、David A Price
DOI:10.1016/s0040-4020(99)00454-8
日期:1999.7
By employing the appropriate chiral bicyclic lactams, the asymmetric total synthesis of four enantiopure azasugars mentioned in the title were successfully achieved. A series of diastereoselective oxidations () followed by diastereoselective reductions (BH3, 9-BBN) gave good yields of the trisubstituted (16) and tetrasubstituted (2,3,4) pyrrolidine and piperidines respectively.