Conjugate addition of chloride to α,β-unsaturated chiral imides promoted by BCl3-derivatives. Part II
摘要:
The diastereoselective hydrochlorination of alpha,beta-unsaturated chiral imides by reaction with BCl(2)OR or BCl(OR)(2) type reagents is described. Complete diastereoselectivity is achieved through the use of new oxazolidin-2-ones ad hoc prepared for this purpose from (S)-tryptophan. An hypothesis on the donor-acceptor interactions, between the substrate and the Lewis acids, that drive the attack of the chloride preferentially to one face of the alkenoyl chain is reported.