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Título
Diamine Catalyzed Addition of ZnEt2 to PhC(O)CF3: Two Mechanisms and Autocatalytic Asymmetric Enhancement
Autor
Año del Documento
2014
Editorial
Wiley
Descripción
Producción Científica
Documento Fuente
Chemistry - A European Journal, 2014, vol. 20, Issue 45, p. 14800–14806
Abstract
NMR studies of the catalytic addition reaction of ZnEt2 to PhC(O)CF3 in the presence of three very efficient catalysts [TMEDA, tBuBOX, and L; where L is a chiral diamine synthesized from optically pure (R,R)-1,2-diphenylethylenediamine and (S)-2,2'-bis-(bromomethyl)-1,1'-binaphthalene] reveal large differences in their behavior. For the ligands TMEDA and tBuBOX, the catalysis shows no unusual features and proceeds via [(N?N)Zn(Et){OC(CF3 )(Et)Ph}]. For N?N?L, the observation of autocatalytic asymmetric enhancement during the catalysis, and unusual inverse concentration dependence on the reaction rate, indicate the participation of an additional novel catalytic cycle that goes through a dinuclear intermediate containing one ZnEt2 and one ZnEt fragment connected by N?N and OR bridges. Interestingly, the (19) F NMR signals of the main product of the reaction ([Zn(Et){OC*(CF3 )(Et)Ph}]2 ) allowed us to assess the enantioselectivity of the processes in situ without the assistance of chiral chromatography.
Materias (normalizadas)
Catalyst
ISSN
0947-6539
Revisión por pares
SI
Patrocinador
Ministerio de Economía, Industria y Competitividad (CTQ2013-48406-P)
Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. GR169 and VA256U13)
Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. GR169 and VA256U13)
Idioma
eng
Derechos
openAccess
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