Bidentates versus Monodentates in Asymmetric Hydrogenation Catalysis: Synergic Effects on Rate and Allosteric Effects on Enantioselectivity
作者:David W. Norman、Charles A. Carraz、David J. Hyett、Paul G. Pringle、Joseph B. Sweeney、A. Guy Orpen、Hirrahataya Phetmung、Richard L. Wingad
DOI:10.1021/ja800858x
日期:2008.5.1
preactivation in the asymmetric hydrogenation studies), the products are identified as the solvento species [Rh(PMePh 2)( L 1a )(S) 2]BF 4 ( 5'), [Rh(S) 2(PMePh 2) 2]BF 4 ( 6') and [Rh(S) 2( L 1a ) 2]BF 4 ( 7') and are formed in the same 2:1:1 ratio. The reaction of M with 0.5 equiv of [Rh(cod) 2]BF 4 gives exclusively the heteroligand complex cis-[Rh(PMePh 2) 2( L 1a ) 2]BF 4 ( 8), an analogue of 4a. The
C 1-对称膦基/亚膦酸酯配体通过 Ph 2P(CH 2) 2P(NMe 2) 2 与 (S)-1,1'-bi-2-naphthol(得到 LA)或(S)的反应制备-10,10'-bi-9-phenanthrol(给 LB )。外消旋 10,10'-bi-9-phenanthrol 是由菲以 44% 的总产率分三步合成的。配合物 [PdCl 2( LA,B )] ( 1a, b), [PtCl 2( LA,B )] ( 2a, b), [Rh(cod)( LA,B )]BF 4 ( 3a, b) [Rh(LA,B) 2]BF 4 ( 4a, b) 和[Rh( LA,B ) 2 ] BF 4 ( 4a, b) 已被报道并确定了1a 的晶体结构。(31)P NMR 研究表明 M,单齿化合物、PMePh 2 和甲基单亚膦酸酯 L 1a(基于 (S)-1,1'-bi-2-naphthol)的 1:1