Highly Enantioselective Conjugate Addition of Nitroalkanes to Alkylidenemalonates Using Efficient Phase-Transfer Catalysis of N-Spiro Chiral Ammonium Bromides
- 1 September 2004
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 126 (38) , 11790-11791
- https://doi.org/10.1021/ja047047v
Abstract
Highly enantioselective conjugate addition of nitroalkanes to alkylidenemalonates has been accomplished for the first time by the utilization of efficient phase-transfer catalysis of N-spiro C2-symmetric chiral quaternary ammonium bromide 1. For instance, simple mixing of nitropropane (2, R 1 = Et), diisopropyl benzylidienemalonate (3, R 2 = Ph), Cs2CO3 (1 equiv), and (S,S)-1 (1 mol %) in toluene at 0 °C for 2.5 h gave rise to the desired conjugate addition product 4 (R1 = Et, R2 = Ph) quantitatively (anti/syn = 86:14) with 97% ee (anti isomer). The applicability of this procedure has been demonstrated with other representative alkylidenemalonates and nitroalkanes. Since 4 can be readily transformed into the corresponding γ-amino acid hydrochloride 5 without loss of diastereo- and enantioselectivity, the present method provides a new and practical access to various optically active γ-amino acid derivatives.Keywords
This publication has 10 references indexed in Scilit:
- Synthesis and applications of C2-symmetric guanidine basesTetrahedron Letters, 2003
- Metallaoxetanes and Carbenes from Diolates in High-Valent Rhenium Oxo Chemistry: The Importance of the Coordination NumberAngewandte Chemie International Edition in English, 2003
- The Absolute Configuration of BromochlorofluoromethaneAngewandte Chemie International Edition in English, 2002
- Organocatalytic Asymmetric Conjugate Addition of Nitroalkanes to α,β-Unsaturated Enones Using Novel Imidazoline CatalystsThe Journal of Organic Chemistry, 2002
- The Nitro Group in Organic SynthesisPublished by Wiley ,2001
- Catalytic Asymmetric Conjugate Addition of Nitroalkanes to CycloalkenonesOrganic Letters, 2000
- Catalytic asymmetric Michael addition of nitromethane to enones controlled by (R)-LPBTetrahedron Letters, 1998
- Catalytic enantioselective Michael addition reactions of α-nitroesters to α,β-unsaturated ketonesTetrahedron: Asymmetry, 1997
- Asymmetric Michael addition of nitroalkanes to prochiral acceptors catalyzed by proline rubidium saltsTetrahedron, 1997
- Synthesis and investigation of a hindered, chiral, bicyclic guanidineTetrahedron: Asymmetry, 1995