Generation and Alkylation of .ALPHA.-Lithio-Se,O-heteroacetals, and Stereoselective Cyclization of Olefinic Se,O-Heteroacetals.
作者:Mitsuhiro YOSHIMATSU、Michiyo FUJIMOTO、Hiroshi SHIMIZU、Mikio HORI、Tadashi KATAOKA
DOI:10.1248/cpb.41.1160
日期:——
Generation of α-lithio-Se, O-heteroacetals was accomplished by direct deprotonation of O-methoxyethylselenoacetals with lithium 2, 2, 6, 6-tetramethylpiperidide. Alkylation of the α-lithioheteroacetals smoothly proceeded to give the products 6 and 7. Olefinic Se, O-heteroacetals 6c and 6d were cyclized via α-seleno carbenium ions generated by selective C-O bond cleavage with titanium tetrachloride to provide the cyclohexane derivatives 8a and 8b, respectively.
用 2, 2, 6, 6-四甲基哌啶锂直接对 O-甲氧基乙基硒乙醛进行去质子化,生成了 α-硫代-Se,O-杂乙醛。α-硫代杂庚基乙醛的烷基化反应顺利进行,得到产物 6 和 7。烯烃 Se、O-杂乙醛 6c 和 6d 通过四氯化钛选择性 C-O 键裂解生成的 α-硒鎓离子环化,分别得到环己烷衍生物 8a 和 8b。