Solvent-free Wittig olefination with stabilized phosphoranes—scope and limitations
作者:Thies Thiemann、Masataka Watanabe、Yasuko Tanaka、Shuntaro Mataka
DOI:10.1039/b311894k
日期:——
Neat mixtures of arene/hetarenecarbaldehydes, alkanals as well as alkenals with alkyl (triphenylphosphoranylidene)acetates react exothermally to furnish the corresponding alkenes. In certain cases, heating has to be provided externally. Reaction times are short and yields are generally very high. Neat mixtures of ketones and alkyl (triphenylphosphoranylidene)acetates react preferentially under microwave irradiation. The better stabilized phosphoranes do not react in the solid state with aldehydes or ketones under conventional heating, but necessitate microwave irradiation, although not all of the phosphoranes have been found to be stable under microwave irradiation at 500 W (2450 MHz).
纯净的芳烃/杂芳烃醛、烷醛以及烯醛与烷基(三苯基磷铵基)醋酸酯发生放热反应,生成相应的烯烃。在某些情况下,需要外部加热。反应时间短,产率通常很高。纯净的酮和烷基(三苯基磷铵基)醋酸酯在微波照射下优先发生反应。稳定性较好的磷烷在固态下与醛或酮在常规加热下不反应,而需要微波照射,尽管并非所有的磷烷在500 W(2450 MHz)的微波照射下都被发现是稳定的。