RT info:eu-repo/semantics/article
T1 Diamine Catalyzed Addition of ZnEt2 to PhC(O)CF3: Two Mechanisms and Autocatalytic Asymmetric Enhancement
A1 Calvillo Barahona, María de las Mercedes
A1 Casares González, Juan Ángel
A1 Cordovilla, Carlos
A1 Genov, Miroslav N.
A1 Martínez de Ilarduya Martínez de Ilarduya, Jesús María
A1 Espinet Rubio, Pablo
K1 Catalyst
AB 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.
PB Wiley
SN 0947-6539
YR 2014
FD 2014
LK http://uvadoc.uva.es/handle/10324/21720
UL http://uvadoc.uva.es/handle/10324/21720
LA eng
NO Chemistry - A European Journal, 2014, vol. 20, Issue 45, p. 14800–14806
NO Producción Científica
DS UVaDOC
RD 28-nov-2024