An efficient method for the direct peroxygenation of various olefinic compounds with molecular oxygen and triethylsilane (Et3SiH) was developed by the use of a catalytic amount of a bis(1,3-diketonato)cobalt(II) complex. According to the above method, 1-phenyl-3-triethylsilydioxybutane (2) was directly produced from 4-phenyl-1-butene (1) by means of a reaction with O2 and Et3SiH at room temperature. Styrene (3) and ethyl acrylate (5a) were also smoothly peroxygenated to give 1-phenyl-1-triethylsilyldioxyethane (4) and ethyl 2-triethylsilyldioxypropionate (6a) by using a small amount of t-BuOOH as an initiator. The successive desilylation of 6a and reduction of the resulting ethyl 2-hydroperoxypropionate (8a) afforded the corresponding alcohol, ethyl lactate (10a), in a high yield. The synthetic utility of the present peroxygenation reaction was demonstrated in the preparation of α-hydroxy esters 10a–e from several α,β-unsaturated esters 5a–e via the corresponding triethylsilyldioxy derivatives.
一种使用双(1,3-二酮基)
钴(II)配合物催化剂对各种烯烃化合物进行分子氧和三乙基
硅烷(Et3SiH)直接过氧化的高效方法已被开发。根据上述方法,通过在室温下使用O2和Et3SiH与
4-苯基-1-丁烯(1)反应,直接生成了1-苯基-3-三乙基
硅氧基
丁烷(2)。此外,
苯乙烯(3)和
丙烯酸乙酯(5a)也能顺利地进行过氧化反应,使用少量t-BuOOH作为
引发剂,分别得到1-苯基-1-三乙基
硅氧基
乙烷(4)和乙基2-三乙基
硅氧基
丙酸酯(6a)。接着对6a进行脱
硅基化反应,并将其产物乙基2-氢过氧化
丙酸酯(8a)还原,以高产率获得了相应的醇,即
乙醇酸乙酯(10a)。本过氧化反应的合成实用性通过从几种α,β-不饱和酯5a–e制备相应的三乙基
硅氧基衍
生物,进而合成α-羟基酯10a–e得到了展现。