Regioselective 1,4-Conjugate Addition of Grignard Reagents to Nitrodienes in the Presence of Catalytic Amounts of Zn(II) Salts
作者:Ramesh C. Dhakal、R. Karl Dieter
DOI:10.1021/ol500114m
日期:2014.3.7
Grignard reagents undergo facile regioselective 1,4-conjugate addition to nitrodienes in the presence of catalyticamounts of Zn(II) salts with excellent yields. A wide range of ligands such as alkyl, aryl, heteroaryl, allyl, vinyl, 1-alkynyl, and alkoxy ligands were transferred, while a thiolate ligand afforded 1,6-regioselectivity. The reactions were successfully carried out on δ-alkyl- or aryl-substituted
Asymmetric Synthesis of 2-Alkyl(Aryl)-2,3-dihydro-4-pyridones by Addition of Grignard Reagents to Chiral 1-Acyl-4-methoxypyridinium Salts
作者:Daniel L. Comins、Sajan P. Joseph、R. Richard Goehring
DOI:10.1021/ja00090a019
日期:1994.6
Grignard addition to a chiral 1-acyl-4-methoxypyridinium salt provides synthetically useful 2-alkyl(aryl)-2,3-dihydro-4-pyridones in high diastereomeric excess
Synthesis of <i>N</i>-Boc-Propargylic and Allylic Amines by Reaction of Organomagnesium Reagents with <i>N</i>-Boc-Aminals and Their Oxidation to <i>N</i>-Boc-Ketimines
作者:Taichi Kano、Ryohei Kobayashi、Keiji Maruoka
DOI:10.1021/acs.orglett.5b03446
日期:2016.1.15
N-Boc-protected propargylic and allylic amines were synthesized by the reaction between N-Boc-aminals and organomagnesiumreagents through the in situ generated N-Boc-imine intermediates. The obtained N-Boc-propargylic amines could be readily converted into unprecedented N-Boc-ketimines by oxidation with manganese dioxide.
Regio- and Stereoselective 1,2-Dihydropyridine Alkylation/Addition Sequence for the Synthesis of Piperidines with Quaternary Centers
作者:Simon Duttwyler、Shuming Chen、Colin Lu、Brandon Q. Mercado、Robert G. Bergman、Jonathan A. Ellman
DOI:10.1002/anie.201310517
日期:2014.4.7
example of C alkylation of 1,2‐dihydropyridines with alkyl triflates and Michael acceptors was developed to introduce quaternary carbon centers with high regio‐ and diastereoselectivity. Hydride or carbon nucleophile addition to the resultant iminium ion also proceeded with high diastereoselectivity. Carbon nucleophile addition results in an unprecedented level of substitution to provide piperidine rings
开发了 1,2-二氢吡啶与烷基三氟甲磺酸酯和迈克尔受体的 C 烷基化的第一个例子,以引入具有高区域选择性和非对映选择性的季碳中心。氢化物或碳亲核试剂加成到所得亚胺离子也具有高非对映选择性。碳亲核试剂加成导致前所未有的取代水平,以提供具有相邻四取代碳原子的哌啶环。
Regioselective Nucleophilic Addition of Organometallic Reagents to 3-Geminal Bis(silyl) <i>N</i>-Acyl Pyridinium
作者:Ya Wu、Linjie Li、Hongze Li、Lu Gao、Hengmu Xie、Zhigao Zhang、Zhishan Su、Changwei Hu、Zhenlei Song
DOI:10.1021/ol500302r
日期:2014.4.4
bis(silyl) N-acyl pyridinium has been described. Geminal bis(silane) shows contrasting roles that lead to different regioselectivities for the addition of different nucleophiles: its steric effect dominates to favor 1,6-addition of alkyl, vinyl, and aryl organometallicreagents; its directing effect dominates to favor 1,2-addition of less sterically demanding alkynyl Grignard reagents.