TY - JOUR
T1 - Catalytic asymmetricaza-Morita-Baylis-Hillman reaction of methyl acrylate
T2 - Role of a bifunctional La(O- i Pr)3/linked-BINOL complex
AU - Yukawa, Takafumi
AU - Seelig, Bianca
AU - Xu, Yingjie
AU - Morimoto, Hiroyuki
AU - Matsunaga, Shigeki
AU - Berkessel, Albrecht
AU - Shibasaki, Masakatsu
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/9/1
Y1 - 2010/9/1
N2 - The catalytic asymmetric aza-Morita-Baylis-Hillman reaction using unactivated methyl acrylate is described. A simple Lewis acidic metal catalyst, such as La(OTf)3, was not suitable for the reaction, but rare earth metal alkoxide/linked-BINOL complexes possessing bifunctional Lewis acid and Brønsted base properties efficiently promoted the reaction in combination with an achiral nucleophilic organocatalyst. The combined use of a La(O-iPr)3/(S,S)-TMS-linked-BINOL complex with a catalytic amount of DABCO promoted the aza-Morita-Baylis-Hillman reaction of a broad range of N-diphenylphosphinoyl imines. Products from aryl, heteroaryl, and alkenyl imines were obtained in 67-99% yield and 81-95% ee. It is noteworthy that isomerizable alkyl imines could be employed as well, giving products in 78-89% yield and 94-98% ee. Initial rate kinetic studies as well as kinetic isotope effect experiments using α-deuterio-methyl acrylate support the importance of both the nucleophilicity of La-enolate and the Brønsted basicity of a La-catalyst for promoting the reaction.
AB - The catalytic asymmetric aza-Morita-Baylis-Hillman reaction using unactivated methyl acrylate is described. A simple Lewis acidic metal catalyst, such as La(OTf)3, was not suitable for the reaction, but rare earth metal alkoxide/linked-BINOL complexes possessing bifunctional Lewis acid and Brønsted base properties efficiently promoted the reaction in combination with an achiral nucleophilic organocatalyst. The combined use of a La(O-iPr)3/(S,S)-TMS-linked-BINOL complex with a catalytic amount of DABCO promoted the aza-Morita-Baylis-Hillman reaction of a broad range of N-diphenylphosphinoyl imines. Products from aryl, heteroaryl, and alkenyl imines were obtained in 67-99% yield and 81-95% ee. It is noteworthy that isomerizable alkyl imines could be employed as well, giving products in 78-89% yield and 94-98% ee. Initial rate kinetic studies as well as kinetic isotope effect experiments using α-deuterio-methyl acrylate support the importance of both the nucleophilicity of La-enolate and the Brønsted basicity of a La-catalyst for promoting the reaction.
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U2 - 10.1021/ja103294a
DO - 10.1021/ja103294a
M3 - Article
C2 - 20690698
AN - SCOPUS:77956077305
VL - 132
SP - 11988
EP - 11992
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 34
ER -