Asymmetric Intramolecular Aldol Reaction Mediated by (S)-N-Substituted-N-(2-pyrrolidinylmethyl)amine to Prepare Wieland-Miescher Ketone
摘要:
New or known N-substituted-N-(2-pyrrolidinylmethyl)amine derivatives bearing a variety of alkyl and aryl substituents were easily prepared from N-Boc-proline or N'-Boc-N-(2-pyrrolidinylmethyl)amine. The enantioselectivity of the intramolecular asymmetric aldol reaction mediated by a combination of the amine derivative and TFA to prepare Wieland-Miescher ketone was examined. During the examination, optimal amount of TFA in the reaction was identified.
Various P∗-chiral phosphite-type ligands: their synthesis, stereochemistry and use in Pd-catalysed allylation
作者:Eduard B. Benetsky、Sergey V. Zheglov、Tatiana B. Grishina、Fliur Z. Macaev、Liudmila P. Bet、Vadim A. Davankov、Konstantin N. Gavrilov
DOI:10.1016/j.tetlet.2007.09.125
日期:2007.11
available modular phosphite, phosphoramidite and diamidophosphiteligands with P∗-stereocentres have been prepared from inexpensive optically active precursors. Using these novelligands, up to 91% ee was achieved in Pd-catalysedasymmetric allylic amination. The catalytic performance is affected greatly by the structure of the phosphocentre of the ligand.
Chiral amine catalyzed enantio- and diastereoselective Michael reaction in brine
作者:Sarbjit Singh、Swapandeep Singh Chimni
DOI:10.1016/j.tetasy.2012.06.026
日期:2012.7
Simple pyrrolidine-based chiral amines were synthesized and used for the Michael addition of different ketones to a variety of nitro-olefins in brine. The effect of different surfactants and acids on the yields and stereochemical outcome of the Michael adducts was studied in detail. Chiral amine 1g was found to catalyze the formation of Michael adducts with high enantioselectivity (up to >99%), diastereoselectivity [up to 98:2 (syn:anti)] and yield (up to 94%). (C) 2012 Elsevier Ltd. All rights reserved.