α,β-不饱和芳族(或杂芳族)羧酸与N-卤代琥珀酰亚胺(1当量)和催化四丁基三氟乙酸铵(0.2当量)在二氯乙烷中的反应导致容易的卤代羧化,从而得到相应的(E)-卤化物优异的产量。类似的反应,但具有2当量。的N在乙腈-水中(1-1:1 v / v)中的-卤代琥珀酰亚胺导致相应的α-(二卤代甲基)苯甲醇的排他性形成。此外,已开发出一种结合了Hunsdiecker催化反应(在二氯乙烷中使用三氟乙酸四丁基铵)和Heck偶联(使用乙酸钯/三乙胺/三苯基锑/二氯乙烷)的一锅法,用于合成5-芳基-2,4-戊二烯酸,酯和酰胺,产率中等至良好。通过上述途径合成了天然产物胡椒碱和哌瓜胺。机理和理论研究(通过AM1计算)对当前的卤代羧化反应的机理提供了有用的见解,表明离子途径涉及卤离子跨碳-碳双键的攻击,
Synthesis of 4-Methyldienoates Using a Vinylogous Horner−Wadsworth−Emmons Reagent. Application to the Synthesis of Trichostatic Acid
作者:John T. Markiewicz、Douglas J. Schauer、Joakim Löfstedt、Steven J. Corden、Olaf Wiest、Paul Helquist
DOI:10.1021/jo902422y
日期:2010.3.19
The utility of the unsaturatedphosphonate 1 as a vinylogous Horner−Wadsworth−Emmons reagent was explored in reactions with aldehydes affording 4-methyldienoate esters. Factors that affect E/Z selectivity were studied. A simplified synthesis of trichostatic acid 3 was accomplished to demonstrate utility of this reagent.