Generation of a configurationally stable, enantioenriched α-oxy-α-methylbenzyllithium: Stereodivergence of its electrophilic substitution
作者:Axel Carstens、Dieter Hoppe
DOI:10.1016/s0040-4020(01)90461-2
日期:1994.1
of (R)- or (S)-1-phenylethyl N,N-diisopropylcarbamate with s-butyllithium/TMEDA in unpolar solvents (e.g. ether or hexane) at −78°C produces configurationally stable ion pairs which are substituted stereospecifically by different electrophiles. In several examples, complete stereoretention or inversion, respectively, was achieved. Electrophiles, which have an energetically low LUMO, such as acid chlorides
N,N-二异丙基氨基甲酸酯的(R)-或(S)-1-苯基乙基在s-丁基锂/ TMEDA中在-78°C下进行去质子化反应生成结构稳定的离子对,这些离子对被立体定向取代不同的亲电试剂。在几个例子中,分别实现了完整的立体保持或反转。LUMO能量很低的亲电子试剂,例如酰氯,杂枯烯和三烷基锡氯化物,更喜欢使用前表面攻击。如果离去基团具有与锂阳离子相互作用的高趋势,例如在酯中,则发生保留的表面取代。