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Bifunctional‐Thiourea‐Catalyzed Diastereo‐ and Enantioselective Aza‐Henry Reaction
Author(s) -
Xu Xueg,
Furukawa Tomihiro,
Okino Tomotaka,
Miyabe Hideto,
Takemoto Yoshiji
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500735
Subject(s) - bifunctional , chemistry , enantioselective synthesis , thiourea , nucleophile , lewis acids and bases , piperidine , catalysis , organic chemistry , enantiomeric excess , aryl , adduct , nitroaldol reaction , reagent , medicinal chemistry , combinatorial chemistry , alkyl
Bifunctional thiourea 1 a catalyzes aza‐Henry reaction of nitroalkanes with N ‐Boc‐imines to give syn ‐β‐nitroamines with good to high diastereo‐ and enantioselectivity. Apart from the catalyst, the reaction requires no additional reagents such as a Lewis acid or a Lewis base. The N‐protecting groups of the imines have a determining effect on the chirality of the products, that is, the reaction of N ‐Boc‐imines gives R adducts as major products, whereas the same reaction of N ‐phosphonoylimines furnishes the corresponding S adducts. Various types of nitroalkanes bearing aryl, alcohol, ether, and ester groups can be used as nucleophiles, providing access to a wide range of useful chiral building blocks in good yield and high enantiomeric excess. Synthetic versatility of the addition products is demonstrated by the transformation to chiral piperidine derivatives such as CP‐99,994.