手性山贝蒂12-甲醚的全合成研究

Chiral Total Synthesis of (+)-Montbretyl 12-Methyl Ether and (-)-Montbretyl 12-Methyl Ether

以化学拆分得 ( S) -( -) -α-环柠檬醛 ( 9a)和 ( R) -( +) -α-环柠檬醛 ( 9b)为 A环合成子 ,以对溴苯甲醚为起始原料 ,经 8步反应制得季盐 1 8为 C环合成子 ,经缩合及分子内环化反应可得到全反式构型关键中间体 ( 3) ,再经结构修饰 ,即可对映选择性地得到 ( +) -山贝蒂 1 2 -甲醚 [( +) -Montbretyl1 2 -methyl ether]( 1 a)和 ( -) -山贝蒂 1 2 -甲醚 [( -) -Montbretyl1 2 -methyl ether]( 1 b) ,其中 BF3·Et2

By using ( S ) (-) α cyclocitral(9a) and( R ) (+) α cyclocitral(9b) obtained by chemical resolution as the A ring synthon, and triphenyl phosphonium chloride(18) obtained from p bromoanisole via eight steps as the C ring synthon, the sole trans key intermediate 3 was obtained after the condensation and intracyclization reactions. The structure modification, (+) montbretyl 12 methyl ether(1a) and (-) montbretyl 12 methyl ether(1b) were obtained enantioselectively. The cyclization reaction of BF 3· Et 2O is the key step.