preparation of allylic phosphorusylides directly from Morita–Baylis–Hillman (MBH) alcohols in an environmentally benign manner was developed. With the assistance of a calcium catalyst, the SN2′ process between phosphines and allylic alcohols occurred smoothly, delivering allylic phosphorus salts and calcium-stabilized hydroxide ions. Then, in situ deprotonation gave the allylic phosphorusylides with water as
开发了一种以环境友好的方式直接从森田-贝利斯-希尔曼(MBH)醇制备烯丙基磷酰化物的新策略。在钙催化剂的辅助下,膦与烯丙基醇之间的S N 2'过程顺利进行,并释放出烯丙基磷盐和钙稳定的氢氧根离子。然后,原位去质子化得到烯丙基磷酰化物,水是唯一的副产物。官能化的1,3-二烯部分可通过Wittig烯化作用捕获酰基化物而方便地获得。
作者:Ko Hoon Kim、Cheol Hee Lim、Jin Woo Lim、Jae Nyoung Kim
DOI:10.1002/adsc.201301169
日期:2014.3.10
An efficient intramolecular arene‐alkene oxidativecoupling of 1,4‐diaryl‐1,3‐butadienes has been developed involving the use of a 2,3‐dichloro‐5,6‐dicyano‐para‐benzoquinone (DDQ)/acid catalyst. The reaction involves the generation of a radical cation by abstraction of an electron from the substrate with DDQ, an intramolecular Friedel–Crafts‐type reaction, and the loss of hydrogen radical.
Selective Preparation of Functionalized Dienes from Allylic Phosphonium Salts through the Wittig Reaction
作者:Marcus M. Sá、Lidiane Meier
DOI:10.1002/hc.21104
日期:2013.9
A convenient and general method for the synthesis of stereochemicallydefined dienes from allylic phosphonium salts under simple conditions is described. Selective preparation of trisubstituted dienes was performed with good-to-excellent yields in mild basic aqueous medium. Preparation of 3-deuterated products was also readily achieved when H2O was replaced with D2O as the solvent.