ketones. Rh4(CO)12 and [Rh(COD)(DPPB)]ClO4 also catalyze the reaction of enol trimethylsilyl with acetals or ketals, whereas [Rh(COD)(DPPB)PF6 does not. When [Rh(COD)(DPPB)ClO4 is used as the catalyst, this type of aldol reaction is extended to the one-pot synthesis of trisubstituted furans from enol trimethylsilyl ether and α-trimethylsiloxy acetal.
当使用催化量的
铑配合物Rh 4(CO)12或[Rh(COD)(
DPPB)] X(X = PF 6和ClO 4;在中性条件下,COD =环辛基-1,5-二烯,
DPPB = 1,4-双(
二苯基膦基)
丁烷。合适的催化剂能够分离出三种不同类型的羟醛反应产物,即β-三甲基甲
硅烷氧基酮,β-羟基酮和α,β-不饱和酮。Rh 4(CO)12和[Rh(COD)(
DPPB)] ClO 4也催化烯醇三甲基甲
硅烷基与
缩醛或
缩酮的反应,而[Rh(COD)(
DPPB)PF 6则不。当[Rh(COD)(
DPPB)ClO由于使用图4的催化剂,这种类型的醛醇缩合反应扩展到由烯醇三甲基甲
硅烷基醚和α-三甲基甲
硅烷氧基
乙缩醛的一锅法合成三取代
呋喃。