ChemInform Abstract: Asymmetric Alkylation of α-Aryl Substituted Carbonyl Compounds by Means of Chiral Phase Transfer Catalysts. Applications for the Synthesis of (+)-Podocarp-8(14)-en-13-one and of (-)-Wy-16,225, a Potent Analgesic Agent.

ChemInform ◽  
1990 ◽  
Vol 21 (30) ◽  
Author(s):  
W. NERINCKX ◽  
M. VANDEWALLE
Keyword(s):  
Carbonyl Compounds ◽  
Phase Transfer ◽  
Analgesic Agent ◽  
Chiral Phase ◽  
Asymmetric Alkylation ◽  
Phase Transfer Catalysts ◽  
Chiral Phase Transfer Catalysts

Chiral designer phase-transfer catalysts for practical asymmetric synthesis

2005 ◽  
Vol 77 (7) ◽  
pp. 1285-1296 ◽  
Author(s):  
Keiji Maruoka
Keyword(s):  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Butyl Ester ◽  
X Ray Diffraction ◽  
Chiral Phase ◽  
Asymmetric Transformations ◽  
Asymmetric Alkylation ◽  
Phase Transfer Catalysts ◽  
Chiral Phase Transfer Catalysts ◽  
Optically Pure

A series of C2-symmetric, spiro-type chiral quaternary ammonium bromides have been designed as new, purely synthetic chiral phase-transfer catalysts, and readily prepared from commercially available optically pure (R)- or (S)-1,1'-bi-2-naphthol as a basic chiral unit. The structures of the assembled N-spiro chiral quaternary ammonium bromides were unequivocally determined by single-crystal X-ray diffraction analysis. The reactivity and selectivity of these chiral ammonium bromides as chiral phase-transfer catalysts have been evaluated in the asymmetric alkylation of N-(diphenylmethylene)glycine tert-butyl ester under mild liquid–liquid phase-transfer conditions, and the optimization of the reaction variables (solvent, base, and temperature) has also been conducted. Furthermore, the scope and limitations of other asymmetric transformations have been thoroughly investigated with a variety of substrates, in which the advantage of the unique N-spiro structure of our chiral phase-transfer catalysts and dramatic effect of the steric as well as the electronic properties of the aromatic substituents on the 3,3'-position of one binaphthyl moiety have been particularly emphasized.

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