Stereoselective decomposition of the α-diazo carbonyl compounds N2CHCOR [R = Me, Prn, Pri, (CH2)10CH3] catalysed by [RuCl(η5-C5H5)(PPh3)2] (0.1 mol%) in toluene at 65 °C affords quantitatively RCOCHCHCOR carbene dimers, the cis isomers being formed in 95â97% yield; under the same experimental conditions N2CHCOEt gives diethyl maleate in a purity of greater than 99%, the highest value for a stereoselective carbeneâcarbene dimer formation reported to date.
在65°C下,使用[RuCl(η5-
C5H5)(PPh3)2]催化(0.1 mol%)的α-二氮羰基化合物N2CHCOR [R = Me, Prn, Pri, (
CH2)10CH3]在
甲苯中选择性分解,可以定量生成RCOCHCHCOR的卡宾二聚体,其中顺式异构体的产率为95–97%;在相同实验条件下,N2CHCOEt生成的二
乙基马来酸酯纯度超过99%,这是迄今为止报道的立体选择性卡宾–卡宾二聚体形成的最高值。