Stereoselective Synthesis of 2,6-<i>syn</i>-Dimethyl-tetrahydropyran Derivatives, Important Segments of Marine Polycyclic Ethers, by Unique Insertion of the Methyl Group
作者:Michihiro Maemoto、Atsushi Kimishima、Tadashi Nakata
DOI:10.1021/ol9018419
日期:2009.11.5
have a 1′-mesyloxy group at the C2-side chain, with Me3Al effected stereoselective insertion of a methyl group at the C2-position to give 2,6-syn-dimethyl-tetrahydropyran derivatives. This reaction proceeds via removal of the mesyloxy group, 1,2-hydride shift, and stereoselective insertion of a methyl group into the resulting oxonium ion.
用Me 3 Al处理在C2-侧链上具有1'-甲氧基的6-甲基-四氢吡喃衍生物,实现了在C2-位上甲基的立体选择性插入,从而得到2,6-顺-二甲基-四氢吡喃衍生物。该反应通过除去甲磺酰氧基,1,2-氢化物移位以及将甲基立体选择性地插入所得的氧鎓离子中而进行。