摘要:
The reaction of omega-Me3Si- or omega-Me3Ge-substituted 3-butyn-1-ol, 4-pentyn-1-ol, and their derivatives with DIBAL-H and a small trialkylalane, e.g., Me3Al or Et3Al, at 23 degrees C gives, after iodinolysis, the corresponding (Z)-4-iodo-3-buten-1-ols and (Z)-5-iodo-4-penten-1-ols in a highly stereo- and regioselective manner, most probably via endo-dig mode cyclic anti-hydroalumination, while treatment of omega-carbosubstituted 3-butyn-1-ols with Red-Al or LiAlH4 at high temperatures followed by iodinolysis can give the corresponding (Z)-4-iodo-3-buien-1-ols also in a highly regio- and stereoselective manner. (C) 1997 Elsevier Science Ltd.