Synthesis of trihydroxylated pyrrolizidines and indolizidines using cycloaddition reactions of functionalized cyclic nitrones, and the synthesis of (+)- and (−)-lentiginosine
作者:Avril E. McCaig、Kevin P. Meldrum、Richard H. Wightman
DOI:10.1016/s0040-4020(98)00572-9
日期:1998.8
4R)-enantiomer, with suitably-functionalized alkenes has led to the synthesis of the 1,2,6-trihydroxypyrrolizidines 14, 33 and ent-33, and the 1,2,7-trihydroxyindolizidines 22,39 and ent-39. Deoxygenation of two enantiomeric intermediates in these syntheses led to the preparation of the dihydroxylated indolizidine (+)-lentiginosine and its (−)-enantiomer.
3,4- isopropylidenedioxy-的环加成Δ 1吡咯啉-1-氧化物(9),(3小号,4小号)-3,4-二(甲氧基甲氧基) - Δ 1 -pyrroline- Ñ氧化物(28),和其(3 - [R,4 - [R )-对映体,用适当官能化的烯烃已导致1,2,6- trihydroxypyrrolizidines的合成14,33和耳鼻喉科-33,和1,2,7- trihydroxyindolizidines 22,39和耳鼻喉科-39。在这些合成中,两个对映异构体中间体的脱氧导致制备了二羟基化的吲哚唑烷(+)-龙胆草碱及其(-)-对映体。