Acid promoted CIDT for the deracemization of dihydrocinnamic aldehydes with Betti's base
作者:Goffredo Rosini、Claudio Paolucci、Francesca Boschi、Emanuela Marotta、Paolo Righi、Francesco Tozzi
DOI:10.1039/c0gc00013b
日期:——
Racemic α-epimerizable and unfunctionalized aldehydes have been converted into enantiomerically enriched mixtures through a sequence of (i) a conversion into the diastereoisomeric 3-substituted 1-phenyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines by reaction with the (R)- or (S)-1-(α-aminobenzyl)-2-naphthol (Betti's base), (ii) an acid promoted crystallization-induced diastereoisomer transformation (CIDT), and (iii) a clean cleavage of the dihydro-1,3-naphthoxazinic ring of the enriched diastereoisomer, easily collected by filtration, allowing the recovery of the enantiomerically enriched aldehydes and the chiral auxiliary.
对映体的α-可互变和未功能化的醛通过以下步骤转化为富含对映体的混合物:(i) 与(R)-或(S)-1-(α-氨基苄基)-2-萘酚(Betti碱)反应,转化为二面体异构体的3-取代1-苯基-2,3-二氢-1H-萘并[1,2-e][1,3]氧杂啉;(ii) 促酸的结晶诱导二面体异构体转化(CIDT);(iii) 清洁地切割富集的二面体异构体的二氢-1,3-萘氧杂烯环,易于过滤收集,从而回收富含对映体的醛和手性辅助剂。