Stereoselective synthesis of (R)-7-pentylhexahydroazepine-2-thione: Formal precursor of (−)-perhydrohistrionicotoxin
作者:Pierre Duhamel、Mitsuharu Kotera、Benoit Marabout
DOI:10.1016/s0957-4166(00)82359-9
日期:1991.1
The (R)-7-pentylthiocaprolactam 1, a formal precursor of (−)-perhydrohistrionicotoxin 2 is synthetized in four steps using asymmetric alkylation of cyclohexanone. Metalation and alkylation of (R)-imine 3 afford after hydrolysis (R)-2-pentylcyclohexanone 4 with high stereoselectivity (e.e.=78%). The Beckmann type rearrangement of the optically enriched ketone 4 proceeds without racemization. The resulting
(R)-7-戊基硫代己内酰胺1((-)-perhydrohistrionicotoxin 2的正式前体)使用环己酮的不对称烷基化反应通过四个步骤合成。(R)-亚胺3的金属化和烷基化在水解后提供(R)-2-戊基环己酮4,具有高的立体选择性(ee = 78%)。光学富集的酮4的贝克曼型重排不消旋地进行。分两步将所得的7-戊基己内酰胺6转化为(R)-苄基硫代内酰胺,将其通过重结晶纯化,得到光学纯的化合物1(ee> 95%)。