A simple preparation of (R)-(2-cyclopentenyl)acetic acid and (R)-(2-cyclohexenyl)acetic acid using β-diastereoselective radical cyclization in the presence of Lewis acid
作者:Mayumi Nishida、Hiroshi Hayashi、Yousuke Yamaura、Emi Yanaginuma、Osamu Yonemitsu、Atsushi Nishida、Norio Kawahara
DOI:10.1016/0040-4039(94)02216-x
日期:1995.1
The alkenyl radical generated from (−)-8-phenylmenthyl 7-iodo-2,6-heptadienoate smoothly cyclized to afford (R)-(2-cyclopentenyl)acetate with 88% de in 90% yield. (R)-(2-Cyclohexenyl)acetate was also obtained with 84% de in 72% yield under the same conditions. The presence of Lewis acid is essential for high diastereoselectivity and chemical yield.
由(-)-8-苯基薄荷基7-碘-2,6-庚二烯酸酯生成的烯基自由基被平滑地环化,以90%的收率得到88%de的(R)-(2-环戊烯基)乙酸酯。在相同条件下,也以84%的de获得(R)-(2-环己烯基)乙酸酯,产率为72%。路易斯酸的存在对于高非对映选择性和化学收率是必不可少的。