methylthiomethyl-protected hydroxyalkenenitriles that are easily hydrolyzed for subsequent annulations with omega-chloroalkyl Grignard reagents. Deprotonating the gamma-hydroxyalkenenitriles with t-BuMgCl followed by addition of omega-chloroalkyl Grignard reagents triggers a conjugate addition-alkylation sequence leading exclusively to cis-octalins, hydrindanes, and decalins. Stereoelectronic control favors an axial
不饱和甲
硅烷基
氰醇与
DMSO-Ac2O的O-烷基化反应会引发重排,生成甲
硫基甲基保护的羟基烯腈,后者易于
水解,可随后用ω-
氯烷基
格氏试剂进行环化。用t-BuMgCl对γ-羟基烯腈进行去质子化,然后添加ω-
氯烷基
格氏试剂,会触发共轭加成烷基化序列,仅导致顺式八氢
萘,氢化
茚和十氢化
萘。立体电子控制有利于轴向共轭物加成,从而产生特别反应性的构象异构体,该构象异构体迅速环化为顺式稠合的双环腈,而通过逐步的顺序生成环状的翻转的构象异构体,则允许进入非对映体反式十氢化
萘。总的来说,