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Sugar‐Based Organocatalyst for the Diastereoselective Desymmetrization of Dibenzylideneacetones
Author(s) -
Pinheiro Danielle L. J.,
Batista Gabriel M. F.,
Gonçalves Jaqueline R.,
Duarte Talita N.,
Amarante Giovanni W.
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201501393
Subject(s) - chemistry , desymmetrization , stereocenter , yield (engineering) , organocatalysis , adduct , enantioselective synthesis , organic chemistry , stereochemistry , sugar , catalysis , materials science , metallurgy
A Brønsted acid catalyzed highly regio‐ and diastereoselective desymmetrization of dibenzylideneacetones in the presence of azlactones is described (only 1,4 addition, > 20:1 dr ). A novel organocatalyst based on D ‐galactose was synthesized and applied in this reaction. In terms of product, a new C–C σ‐bond and two stereogenic centers are created, one of which is quaternary. The relative stereochemistry was assigned by comparison of both chiral HPLC traces and 13 C NMR spectroscopic data as being 1,2‐ anti . One of the final Michael‐type adducts could be converted into an N ‐protected α‐functionalized amino acid in good yield and with no loss of diastereoselectivity.