of aldehyde by the catalysis of a chiraltitaniumcomplex derived from DTBP-H8-BINOL. The reaction is performed with good stoichiometry [1.5 equiv each of Grignard reagents and ClTi(OiPr)3] at a low catalyst loading (2 mol %), affording a variety of chiral secondary alcohols in high enantioselectivity and yields and, hence, realizing an asymmetric version of the Grignard reaction in an indirect manner
由格氏试剂和ClTi(O i Pr)3原位生成的烷基钛试剂可通过催化衍生自DTBP-H 8 -BINOL的手性钛配合物用于醛的对映选择性烷基化反应,而无需进一步操作。该反应以良好的化学计量[1.5当量的格氏试剂和ClTi(O i Pr)3 ]在低催化剂负载量(2mol%)下进行,从而以高对映选择性和收率提供了多种手性仲醇,因此,间接实现格氏反应的不对称形式。
Catalytic Asymmetric Alkylation of Aldehydes with Grignard Reagents
作者:Yusuke Muramatsu、Toshiro Harada
DOI:10.1002/anie.200704963
日期:2008.1.25
Catalytic Enantioselective Alkylation and Arylation of Aldehydes by Using Grignard Reagents
the resulting mixed titanium reagents undergo addition to aldehydes with high enantioselectivities (typically >90% ee) and high yields. The method is applicable to various combination of aldehydes (R 1 CHO; R 1 = aryl, heteroaryl, 1-alkenyl, and alkyl) and Grignard reagents (R 2 MgX; R 2 = primary alkyl and aryl). Thus, a variety of enantiomerically enriched secondary alcohols (R 1 CH*(OH)R 2 ) can