邻位官能化的偶氮苯在分子开关后备受追捧,因为它们可以调整为在可见光范围内吸收,并且 ( Z )-异构体可以具有高热半衰期。为了能够直接访问这些目标,我们开发了一种通过新型邻位取代偶氮苯功能化二芳基碘盐的合成路线。在温和、无过渡金属的条件下,将偶氮苯部分选择性地转移至 O-、N-、C- 和 S- 亲核试剂,可以获得前所未有的邻位取代偶氮苯。研究了试剂的光开关特性,并通过 X 射线晶体学确定了结构。
Several 2-phosphinoazobenzenes, which are in equilibrium with inner phosphonium salts, were synthesized. Effects of substituents, solvents, and acidic additives on their equilibria are described. T...
A new approach for highly regioselective iodination of azobenzenes with alkyl iodide as the iodinating reagent enabled by Rh-catalyzedoxidativeC–Hactivation has been developed. By changing the oxidant, various mono- and di-iodinated azobenzenes were smoothly obtained in moderate to excellent yields, respectively. The preliminary mechanistic study reveals that the reaction process might undergo electrophilic
Experimental and Theoretical Investigation of the Coarctate Cyclization of (2-Ethynylphenyl)phenyldiazenes
作者:Laura D. Shirtcliff、Timothy J. R. Weakley、Michael M. Haley、Felix Köhler、Rainer Herges
DOI:10.1021/jo049011r
日期:2004.10.1
A new route to substituted 2-phenyl-2H-indazoIes through the cyclization of (2-ethynylphenyl)-phenyldiazenes is presented. A coarctate reaction pathway forms the isoindazole carbene under neutral conditions, at moderate temperatures, and without the requirement of a carbene stabilizer. A wide variety of previously unknown diazene precursors was synthesized and cyclized. Trapping of the carbene with a silyl alcohol followed by deprotection affords the 3-hydroxymethyl-2-phenyl-2H-indazoles in good overall yield. The free carbene could also be trapped as a [2 + 1] cycloadduct with 2,3-dimethyl-2-butene.
Synthesis of 2<i>H</i>-Indazoles via Lewis Acid Promoted Cyclization of 2-(Phenylazo)benzonitriles
作者:Laura D. Shirtcliff、Jazmin Rivers、Michael M. Haley
DOI:10.1021/jo060965m
日期:2006.8.1
Lewis-acid promoted "coarctate" cyclization of 10 2-(phenylazo) benzonitrile derivatives furnishes the isoindazole ring system in ca. 65-95% yield. A plausible mechanism for this unusual transformation is proposed.