作者:Seiji Yamaguchi、Akiko Arisawa、Naoko Katoh、Keiko Hatanaka、Hajime Yokoyama、Yoshiro Hirai
DOI:10.1246/bcsj.70.2215
日期:1997.9
The stereochemistry was studied concerning the ring expansion of some 2-isopropenylcyclopropane-1-carbonyl compounds to 2,5-dihydro-3-methyloxepin derivatives. The LAH reduction of dimethyl 2-isopropenylcyclopropane-1,1-dicarboxylate (1aa) gave the corresponding diol, and a subsequent Swern oxidation gave a seven-membered 4,7-dihydro-6-methyloxepin-3-carbaldehyde. A DIBAL reduction of 1aa gave two isomeric hydroxymethyl carboxylic esters, and a subsequent Swern oxidation of methyl 1-hydroxymethyl-t-2-isopropenylcyclopropane-r-1-carboxylate caused a ring expansion to give methyl 4,7-dihydro-6-methyloxepin-3-carboxylate; however, a similar Swern oxidation of methyl 1-hydroxymethyl-c-2-isopropenyl-cyclopropane-r-1-carboxylate caused no ring expansion to give methyl 1-formyl-c-2-isopropenylcyclopropane-r-1-carboxylate.
研究了一些 2-异丙烯基环丙烷-1-羰基化合物向 2,5-二氢-3-甲基氧杂卓衍生物扩环的立体化学过程。2-isopropenylcyclopropane-1,1-dicarboxylate (1aa) 的 LAH 还原反应得到了相应的二元醇,随后的 Swern 氧化反应得到了七元的 4,7-二氢-6-甲基氧杂卓-3-甲醛。1aa 的 DIBAL 还原反应产生了两个异构的羟甲基羧酸酯,随后 1- 羟甲基-t-2-异丙烯基环丙烷-r-1-羧酸甲酯的 Swern 氧化反应导致环扩张,产生了 4,7-二氢-6-甲基氧杂卓-3-羧酸甲酯;然而,对 1-羟甲基-c-2-异丙烯基环丙烷-r-1-羧酸甲酯进行类似的 Swern 氧化反应不会导致环扩大,从而得到 1-甲酰基-c-2-异丙烯基环丙烷-r-1-羧酸甲酯。