reaction requiring isomerization of the C-Sn to the O-Sn enolate. The Pd catalyzed condensation of cyanomethyltributyltin with reactive aldehydes, such as nitrobenzaldehydes, took place at ambient temperatures in polar solvents to give high yields of condensation products. No reaction occurred with aldehydes such as benzaldehyde. Only low stereoselectivity (10-34% ee) was observed when (-) DIOP or (-)BPPM
在动力学控制下(-78°),
环己酮或丙苯酮的烯醇
锡与各种醛的反应主要产生了三个醇醛,非对映选择性高达95:5。在较高温度(+ 45°)下,观察到主要的赤型选择性。
苯乙酮的烯醇
锡烷以O-Sn(可能是E-异构体)和C-Sn衍
生物。-78°与O-Sn烯酸酯迅速发生反应,进一步的反应需要C-Sn异构化为O-Sn烯酸酯。Pd催化的
氰基甲基三
丁基锡与反应性醛(如硝基
苯甲醛)的缩合反应在环境温度下于极性溶剂中进行,从而获得高收率的缩合产物。与醛如
苯甲醛没有反应发生。当(-)D
IOP或(-)
BPPM用作手性
膦配体时,仅观察到低的立体选择性(10-34%ee)。