Modified Fry Cyanation of a Chiral Pyridinium Salt: Asymmetric Syntheses of (-)-Coniine and (-)-Solenopsin A
作者:Van Ha Vu、Laurie-Anne Jouanno、Adèle Cheignon、Thierry Roisnel、Vincent Dorcet、Sourisak Sinbandhit、Jean-Pierre Hurvois
DOI:10.1002/ejoc.201300595
日期:2013.8
The synthesis of chiral 2-cyano-Δ4-tetrahydropyridine 5 was carried out in 85 % yield through a modified two-step Fry reductive cyanation of pyridinium salt (+)-3c that used lithium triethylborohydride as the hydride donor. An alkylation–reduction sequence provided 2-alkyl-substituted tetrahydropyridines (+)-10a and (+)-10b in 72–75 % yield after chromatographic purification. This protocol has been
Synthesis of chiral isoquinuclidines and determination of their absolute configuration
作者:M. Mehmandoust、C. Marazano、R. Singh、B. Gillet、M. Césario、J.-L. Fourrey、B.C. Das
DOI:10.1016/s0040-4039(00)80512-2
日期:1988.1
A route to 1,2-dihydropyridines N1-substituted with chiral auxiliaries has been developed starting from commercially available chiral amines. Cycloaddition between these dihydropyridines and methyl acrylate gave, in moderate d.e., isoquinuclidines of good enantiomeric purity whose absolute configuration has been established.
1,4-dihydropyridines from dithionite reduction of pyridinium salts without electron-withdrawing groups as substituents
作者:Yung-Sing Wong、Christian Marazano、Dino Gnecco、Bhupesh C. Das
DOI:10.1016/s0040-4039(00)75796-0
日期:1994.1
Conditions have been established for the sodium dithionite (Na2S2O4) reduction of pyridiniumsalts 1 lacking electron-withdrawing substituents to their corresponding 1,4-dihydropyridines (1,4-DHPs) 2, a reaction which was previously reported to fail. The importance of hydrophobic effects for this reduction to take place could be recognized from the results obtained. The present procedure offers a very
已经建立了亚硫酸钠(Na 2 S 2 O 4)还原没有吸电子取代基的吡啶鎓盐1到其相应的1,4-二氢吡啶(1,4-DHPs)2的条件,该反应先前被报道为失败。从获得的结果可以认识到疏水作用对于这种减少发生的重要性。本方法提供了通往许多1,4-DHP 2,特别是一系列手性衍生物如5和9的非常方便的途径。