Secondary Allyltitanium(IV) Reagents in Aldehyde Allylation I: Extension of the Hoppe Reaction to γ-Alkoxy Secondary Allyl Carbamates
作者:Jacques Courtieu、Janick Ardisson、Patrick Razon、Sylvie Dhulut、Sophie Bezzenine-Lafollée、Ange Pancrazi
DOI:10.1055/s-2004-834912
日期:——
An efficient access to optically active (R)- or (S)-γ-alkoxy allyltitanium(IV) intermediates, in aldehyde allylation reactions, is described. Enantiomeric γ-alkoxy secondary allyl carbamates (R)- and (S)-14 were first prepared. Determination of their enantiomeric excess was realised on the corresponding deuterated isotopic derivatives by NMR in chiral liquid media. Subsequent aldehyde allylation reaction
描述了在醛烯丙基化反应中有效获得光学活性 (R)-或 (S)-γ-烷氧基烯丙基钛 (IV) 中间体的方法。首先制备对映体γ-烷氧基仲氨基甲酸烯丙酯(R)-和(S)-14。在手性液体介质中通过 NMR 对相应的氘代同位素衍生物进行了对映体过量的测定。随后在 Hoppe n-BuLi.(-)-sparteine/Ti(Oi-Pr) 4 或 n-BuLi.TMEDA/Ti(Oi-Pr) 4 条件下与丙醛进行醛烯丙基化反应,得到对映异构体均烯丙醇 15 或ent-15 的产率为 90%,ed 为 100%,ee 为 80%。