outcome of the alkylation of a variety of phenylglycinol-derived oxazolopiperidone lactams is studied. The influence of the configuration of the C-8a stereocenter and the effect of the substituents at the C-8 and C-8a positions on the stereoselectivity of the reaction are discussed. The synthetic utility of these alkylation reactions is illustrated with the synthesis of cis and trans 3,5-disubstituted, 2
Regioselective Endocyclic Oxidation of Enantiopure 3‐Alkylpiperidines: Synthesis of (3<i>S</i>,5<i>S</i>)‐(‐)‐3‐Ethyl‐5‐Methylpiperidine
作者:Alejandro Castro、Jorge Juárez、Dino Gnecco、Joel L. Terán、Laura Orea,、Sylvain Bernès
DOI:10.1080/00397910500466454
日期:2006.3.1
An efficient regioselective endocyclic oxidation of enantiopure 3-alkylpiperidines 1( a-c) with bromine in acetic acid to generate the corresponding 5-alkylpiperidin-2-ones 3(a-c) as main product is described. In addition, starting from 3a or 3b, the synthesis of (3S,5S)-(-)-3-ethyl-5-methylpiperidine 6 (.) HCl was achieved. Finally, the X-ray single-crystal analysis of compound 4 is reported.