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Synthesis of d ‐mannitol‐based crown ethers and their application as catalyst in asymmetric phase transfer reactions
Author(s) -
Nemcsok Tamás,
Rapi Zsolt,
Keglevich György,
Grün Alajos,
Bakó Péter
Publication year - 2018
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.22800
Subject(s) - chemistry , catalysis , chalcone , phase transfer catalyst , benzaldehyde , michael reaction , organic chemistry , condensation reaction , medicinal chemistry
A few new d ‐mannitol‐based monoaza‐15‐crown‐5 type chiral lariat ethers and 18‐crown‐6 type macrocycles were synthesized. These crown compounds were used as phase transfer catalysts in asymmetric Michael addititons and in a Darzens condensation under mild conditions to afford the corresponding products in a few cases in good to excellent enantioselectivities. In the Michael addition of diethyl acetoxymalonate to trans ‐chalcone, in the addition of diethyl acetamidomalonate to ß ‐nitrostyrene, in the reaction of diethyl bromomalonate with benzylidene malononitriles, in the cyclopropanation reaction of diethyl bromomalonate and 2‐benzylidene‐1,3‐indandione, and in the Darzens condensation of α ‐chloroacetophenone with benzaldehyde, maximum enantioselectivities of 39%, 65%, 99%, 56%, and 62%, respectively, were obtained in the presence of the d ‐mannitol‐based macrocycles as the catalysts.