Electronically Dissymmetric DIPHOS Derivatives Give Higher n:i Regioselectivity in Rhodium-Catalyzed Hydroformylation Than Either of Their Symmetric Counterparts
作者:Charles P. Casey、Evelyn Lin Paulsen、Eckart W. Beuttenmueller、Bernd R. Proft、Brock A. Matter、Douglas R. Powell
DOI:10.1021/ja982117h
日期:1999.1.1
derivatives [3,5-(CF3)2C6H3]2PCH2CH2PPh2 = [DIPHOS−(3,5-CF3,H)] (1), [2-(CF3)C6H4]2PCH2CH2PPh2 = [DIPHOS−(2-CF3,H)] (2), [3,5-(CF3)2C6H3]2PCH2CH2P[2-(CH3)C6H4]2 = [DIPHOS−(3,5-CF3,2-CH3)] (3), and [2-(CF3)C6H4]2PCH2CH2P[2-(CH3)C6H4]2 = [DIPHOS−(2-CF3,2-CH3)] (4) were investigated. Two apical−equatorial chelate isomers were observed for model (diphosphine)Ir(CO)2H complexes of dissymmetric diphosphines 1−4. In
电子不对称 DIPHOS 衍生物 [3,5-(CF3)2C6H3]2PCH2CH2PPh2 = [DIPHOS−(3,5-CF3,H)] (1), [2-(CF3) 对铑催化 1-己烯加氢甲酰化的电子效应)C6H4]2PCH2CH2PPh2 = [DIPHOS−(2-CF3,H)] (2), [3,5-(CF3)2C6H3]2PCH2CH2P[2-(CH3)C6H4]2 = [DIPHOS−(3,5-CF3) ,2-CH3)] (3) 和 [2-(CF3)C6H4]2PCH2CH2P[2-(CH3)C6H4]2 = [DIPHOS-(2-CF3,2-CH3)] (4) 进行了研究。对于不对称二膦 1-4 的模型(二膦)Ir(CO)2H 复合物,观察到两种顶端-赤道螯合异构体。在每种情况下,主要异构体的赤道膦 (96-60%) 都具有吸电子芳基取代基。这些不对称的 DIPHOS 衍生物用于测试赤道膦上的吸电子取代基增加加氢甲酰化