The total synthesis of dihydrocrinine and related compounds
作者:Hiroshi Irie、Shojiro Uyeo、Akira Yoshitake
DOI:10.1039/j39680001802
日期:——
Racemic dihydro-oxocrinine (XVIII) was synthesized from the keto-lactam (X) by a sequence of reactions including the Michael-type cyclization of the αβ-unsaturated keto-lactam (XI) by the use of toluene-p-sulphonic acid. The racemic ketone (XVIII) was resolved into optically active dihydro-oxocrinine (XIX) and dihydro-oxovittatine (XX). The former gave dihydrocrinine (II) or dihydroepicrinine (IV) when reduced by the Meerwein-Ponndorf reaction or by lithium aluminium hydride, respectively. The latter (XX) afforded dihydrovittatine (III) or dihydroepivittatine (V) when similarly reduced.
外消旋二氢-氧分泌宁 (XVIII) 由酮-内酰胺 (X) 通过一系列反应合成,包括使用甲苯-对-磺酸对 αβ-不饱和酮-内酰胺 (XI) 进行 Michael 型环化。外消旋酮(XVIII)被拆分成光学活性的二氢-氧代泌尿素(XIX)和二氢-氧代维生素A(XX)。前者分别通过 Meerwein-Ponndorf 反应或氢化铝锂还原时得到二氢外泌宁 (II) 或二氢表泌宁 (IV)。当类似地还原时,后者(XX)提供二氢维生素E(III)或二氢维生素E(V)。
Bioinspired enantioselective synthesis of crinine-type alkaloids via iridium-catalyzed asymmetric hydrogenation of enones
A bioinspired enantioseletive synthesis of crinine-type alkaloids has been developed by using iridium-catalyzed asymmetric hydrogenation of racemic cycloenones. The method features a biomimetic stereodivergent resolution of the substrates bearing a remote arylated quaternarystereocenter. Using this protocol, 24 crinine-type alkaloids and 8 analogues were synthesized in a concise and rapid way with