<i>N</i>,<i>N</i>-Acetals as <i>N</i>-Acyliminium Ion Precursors: Synthesis and Absolute Stereochemistry of Epiquinamide
作者:Marloes A. Wijdeven、Roel Wijtmans、Rutger J. F. van den Berg、Wim Noorduin、Hans E. Schoemaker、Theo Sonke、Floris L. van Delft、Richard H. Blaauw、Richard W. Fitch、Thomas F. Spande、John W. Daly、Floris P. J. T. Rutjes
DOI:10.1021/ol801490m
日期:2008.9.18
A stereoselectivesynthesis of (+)-epiquinamide is presented in combination with determination of the absolute configuration of the natural product. Key steps in the sequence involved chemoenzymatic formation of an enantiomerically pure cyanohydrin, reductive cyclization to the corresponding cyclic N,N-acetal, and subsequent conversion into a suitable N-acyliminium ion precursor to enable construction
作者:Marloes A. Wijdeven、Floris L. van Delft、Floris P.J.T. Rutjes
DOI:10.1016/j.tet.2010.05.089
日期:2010.7
The synthetic versatility of three chemoenzymatically prepared hydroxypiperidine building blocks has been explored, resulting in a library of enantiopure functionalized piperidines. Key steps involved N-acyliminium ion-mediated CC-bond formation and cross-metathesis reactions, after which full deprotection led to the set of free 3-hydroxypiperidines. (C) 2010 Elsevier Ltd. All rights reserved.
Asymmetric Synthesis of AntimalarialAlkaloids (+)-Febrifugine and (+)-Isofebrifugine
作者:Pei-Qiang Huang、Bang-Guo Wei、Yuan-Ping Ruan
DOI:10.1055/s-2003-40988
日期:——
Diastereoselective α-amidoalkylation of N,O-acetal,derivated from controlled regio and diastereoselective reductionof (S)-N-(4-methoxybenzyl)-3-silyloxyglutarimideprovided two diastereomeric 6-allyl-5-silyloxy-2-piperidinonesin 76:24 selectivity. The transformation of the major diastereomerinto a known advanced intermediate allowed the synthesis of (+)-febrifugineand (+)-isofebrifugine.
Complementary chemoenzymatic routes to both enantiomers of febrifugine
作者:Marloes A. Wijdeven、Rutger J. F. van den Berg、Roel Wijtmans、Peter N. M. Botman、Richard H. Blaauw、Hans E. Schoemaker、Floris L. van Delft、Floris P. J. T. Rutjes
DOI:10.1039/b901670h
日期:——
Two complementary strategies for the synthesis of febrifugine are detailed based on previously developed chemoenzymatic approaches to the 3-hydroxypiperidine skeleton. The introduction of the quinazolone-containing side chain in both strategies was based on an N-acyliminium ion-mediated coupling reaction.