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Probing the “additive effect” in the proline and proline hydroxamic acid catalyzed asymmetric addition of nitroalkanes to cyclic enones
Author(s) -
Hanessian Stephen,
Govindan Subramaniyan,
Warrier Jayakumar S.
Publication year - 2005
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20201
Subject(s) - chemistry , proline , catalysis , hydroxamic acid , amino acid , organic chemistry , stereochemistry , combinatorial chemistry , biochemistry
The effect of chirality and steric bulk of 2,5‐disubstituted piperazines as additives in the conjugate addition of 2‐nitropropane to cyclohexenone, catalyzed by l ‐proline, was investigated. Neither chirality nor steric bulk affects the enantioselectivity of addition, which gives 86–93% ee in the presence of achiral and chiral nonracemic 2,5‐disubstituted piperazines. Proline hydroxamic acid is shown for the first time to be an effective organocatalyst in the same Michael reaction. © 2005 Wiley‐Liss, Inc. Chirality 17:540–543, 2005.