additions to organic carbonyls. Aryl additions of AlArEt2(THF) to aldehydes catalyzed by the titanium(IV) complex of (R)-H8−BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing
一系列AlArEt 2(THF)(Ar = Ph(1a),4-MeC 6 H 4(1b),4-MeOC 6 H 4(1c),4-Me 3 SiC 6 H 4(1d),2-由AlEt 2 Br(THF)与ArMgBr的反应合成
萘基(1e)。在CDCl 3溶液中,1 H NMR光谱表明,AlArEt 2(THF)化合物以AlAr x Et 3- x(THF)(x= 0、1、2或3)。发现AlArEt 2(THF)化合物是不对称芳基加成到有机羰基化合物中的优良化合物,并且是原子经济的试剂。由(R)-H 8 -BINOL的
钛(IV)络合物催化的AlArEt 2(THF)芳基加成醛的反应效率高,反应时间短至1 h,从而以高收率提供芳基加成产物作为独家产物或主要产物以及高达98%ee的优异对映选择性。尽管
乙醛中
乙醛的添加量很小,但这项研究表明,增加AlArEt 2的含量(THF)从1.2到1.4或到1