Alkylation, Aldol, and Related Reactions of <i>O</i>-Alkanoyl- and 2-AlkenoylTEMPOs (2,2,6,6-Tetramethylpiperidine-<i>N</i>-oxyl): Insight into the Reactivity of Their Anionic Species in Comparison with Esters and Amides
作者:Tsutomu Inokuchi、Hiroyuki Kawafuchi
DOI:10.1021/jo0617316
日期:2007.2.1
The lithium anionic species generated from O-alkanoylTEMPOs upon treatment with LDA were first employed as a nucleophile for alkylation, Michael addition, direct aldol reaction, and others. The alkylation occurred smoothly at the methylene carbon, and no alkylation was found in the isobutyryl analogue, while silylation was scarcely attainable. Substitutions of the heteroatom were achieved by reaction
由LDA处理后,由O-烷酰基TEMPO产生的锂阴离子物质首先被用作亲核试剂,用于烷基化,迈克尔加成反应,直接的羟醛反应等。烷基化在亚甲基碳处顺利进行,在异丁酰基类似物中未发现烷基化,而几乎无法获得甲硅烷基化。杂原子的取代是通过与PhSSPh和DEAD反应实现的。这些阴离子物质的反应性成功地扩展到了醛醇缩合反应中,其中丙酰基衍生物具有适度的抗选择性或顺式选择性。在O-巴豆酰基TEMPO上进行串联迈克尔加成的氨基化锂,然后进行醛醇缩合反应。