由于格氏试剂的高反应性,很少公开与醛类直接,高度对映选择性的格氏试剂反应。在该报告中,格氏试剂与双[2-(N,N'-二甲基氨基)乙基]醚(BDMAEE)一起引入,以有效地使其活性失活。因此,由(S)-BINOL-Ti(O i Pr)2催化导致格氏试剂对醛的高度对映选择性烷基化。认为BDMAEE螯合了RMgBr的Schlenk平衡的原位生成的盐MgBr 2和RMgBr与Ti(O i Pr)4的重金属化产生的Mg(O i Pr)Br的螯合作用。镁盐可以积极地促进不希望有的背景反应,生成外消旋体。该螯合作用无疑抑制了Mg盐的催化活性,抑制了不需要的背景反应,并且使得能够被(S)-BINOL-Ti(O i Pr)2催化的高对映选择性加成。因此,与以前的研究相比,没有除去Mg盐的副产物,使用了比RMgBr少的Ti(O i Pr)4,并且在该催化不对称反应中避免了极低的温度。各种烷基格氏试剂中的不对称
herein an unprecedented highly efficient Guerbet‐type reaction at room temperature (catalytic TON up to >6000). This β‐alkylation of secondary methyl carbinols with primary alcohols has significant advantage of delivering higher‐order secondary alcohols in an economical, redox‐neutral fashion. In addition, the first enantioselective Guerbet reaction has also been achieved using a commercially available
Ru-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes via P-Chiral Monophosphorous Ligands
作者:Rui Miao、Yanping Xia、Yifei Wei、Lu Ouyang、Renshi Luo
DOI:10.3390/molecules27123898
日期:——
situ was found to promote an enantioselective addition of aliphaticaldehydes with arylboronic acids, delivering the chiral alcohols in excellent yields and enantioselectivities and exhibiting a broad scope of aliphaticaldehydes and arylboronic acids. The enantioselectivities are highly dependent on the monophosphorous ligands. The utility of this asymmetric synthetic method was showcased by a large-scale
Catalytic Highly Enantioselective Alkylation of Aldehydes with Deactivated Grignard Reagents and Synthesis of Bioactive Intermediate Secondary Arylpropanols
作者:Yi Liu、Chao-Shan Da、Sheng-Li Yu、Xiao-Gang Yin、Jun-Rui Wang、Xin-Yuan Fan、Wei-Ping Li、Rui Wang
DOI:10.1021/jo101351t
日期:2010.10.15
of the high reactivity of Grignard reagents, a direct, highly enantioselective Grignard reaction with aldehydes has rarely been disclosed. In this report, Grignard reagents were introduced with bis[2-(N,N′-dimethylamino)ethyl] ether (BDMAEE) to effectively deactivate their reactivity; thus, a highly enantioselective alkylation of aldehydes with Grignard reagents resulted from catalysis by (S)-BINOL-Ti(OiPr)2
由于格氏试剂的高反应性,很少公开与醛类直接,高度对映选择性的格氏试剂反应。在该报告中,格氏试剂与双[2-(N,N'-二甲基氨基)乙基]醚(BDMAEE)一起引入,以有效地使其活性失活。因此,由(S)-BINOL-Ti(O i Pr)2催化导致格氏试剂对醛的高度对映选择性烷基化。认为BDMAEE螯合了RMgBr的Schlenk平衡的原位生成的盐MgBr 2和RMgBr与Ti(O i Pr)4的重金属化产生的Mg(O i Pr)Br的螯合作用。镁盐可以积极地促进不希望有的背景反应,生成外消旋体。该螯合作用无疑抑制了Mg盐的催化活性,抑制了不需要的背景反应,并且使得能够被(S)-BINOL-Ti(O i Pr)2催化的高对映选择性加成。因此,与以前的研究相比,没有除去Mg盐的副产物,使用了比RMgBr少的Ti(O i Pr)4,并且在该催化不对称反应中避免了极低的温度。各种烷基格氏试剂中的不对称