Enantio- and diastereoselective titanium-TADDOLate catalyzed addition of diethyl and bis(3-buten-1-yl) zinc to aldehydes a full account with preparative details
作者:Dieter Seebach、Albert K. Beck、Beat Schmidt、Yan Ming Wang
DOI:10.1016/s0040-4020(01)89373-x
日期:1994.4
enantioselective addition of alkyl groups from organozinc reagents to aldehydes (19 examples). With 0.05 – 0.20 equiv. of the diisopropoxy-Ti-TADDOLate bearing four 2-naphthyl groups and 1.2 equiv. of Ti(OCHMe2)4 in toluene or ether solution the best results are obtained: ≥ 98 : 2 enantiomer ratios with all types of aldehydes tested (saturated, olefinic, and acetylenic aliphatic, aromatic, and heteroaromatic)
钛(IV)的α,α,α',α'-四芳基-2-单-和-2,2-二取代-1,3-二氧戊环-4,5-二甲醇盐(TADDOLates)用于路易斯酸介导的从有机锌试剂到醛的烷基对映选择性加成(19个实例)。当0.05 – 0.20当量。带有四个2-萘基和1.2当量的二异丙氧基-Ti-TADDOLate的盐。在甲苯或乙醚溶液中制备Ti(OCHMe 2)4可获得最佳结果:≥98:2对映体比例,并且测试了所有类型的醛(饱和,烯烃和炔属脂族,芳族和杂芳族)。亲核加成从(发生硅醛的)面时(R,R)-TADDOLate被使用。-使用手性醛,实现了二乙基锌的非对映选择性加成(7个实例)。在醛中不存在另外的官能团的情况下,非对映选择性不依赖于其手性(“试剂对照”,两个实例)。-将对映选择性地向醛中添加二烷基锌试剂的TADDOLate方法与其他路易斯酸或氨基醇介导的方法进行了比较。给出了完整的实验细节以及通过文献分配获得的某些产品的绝对构型的相关性。