Conversion between Difluorocarbene and Difluoromethylene Ylide
作者:Jian Zheng、Jin-Hong Lin、Ji Cai、Ji-Chang Xiao
DOI:10.1002/chem.201303248
日期:2013.11.4
The interconversion between difluoromethylene ylide and difluorocarbene is described. The difluoromethylene ylideprecursor, Ph3P+CF2CO2−, could be turned into an efficient difluorocarbene reagent, whereas the classical difluorocarbene reagents, HCF2Cl and FSO2CF2CO2TMS, could generate highly reactive difluoromethylene ylide. Thus the Wittig difluoro‐olefination and difluorocyclopropanation could be
描述了二氟亚甲基叶立德和二氟卡宾之间的相互转化。该二氟亚甲基叶立德前体中,Ph 3 P + CF 2 CO 2 - ,也可以变成一个高效的二氟卡宾的试剂,而经典二氟卡宾的试剂,HCF 2 Cl和FSO 2 CF 2 CO 2 TMS,可能会产生高反应性的二氟亚甲基内鎓盐。因此,使用相同的试剂可以选择性地实现Wittig的二氟烯烃化和二氟环丙烷化。另外,从不同卡宾来源获得的叶立德在维蒂希反应中显示出不同的反应性。
Pd-Catalyzed Regioselective Activation of<i>gem</i>-Difluorinated Cyclopropanes: A Highly Efficient Approach to 2-Fluorinated Allylic Scaffolds
作者:Jun Xu、Ebrahim-Alkhalil Ahmed、Bin Xiao、Qian-Qian Lu、Yun-Long Wang、Chu-Guo Yu、Yao Fu
DOI:10.1002/anie.201502308
日期:2015.7.6
An unprecedented Pd‐catalyzedregioselective activation of gem‐difluorinated cyclopropanes induced by CC bond cleavage is reported. It provides a general and efficient access to a variety of 2‐fluoroallylic amines, ethers, esters, and alkylation products in high Z‐selectivity, which are important skeletons in many biologically active molecules. In addition, the transformation represents the first
Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bondactivation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage
A Pd-catalyzed ring-opening sulfonylation of gem-difluorocyclopropanes is reported. This protocol involves C-C bond cleavage, β-F elimination, and allylic coupling to form corresponding 2-fluoroallylic sulfones efficiently with Z-selectivity. Different substrates bearing diverse functional groups are tolerated. Moreover, this method is successfully used for the late-stage derivation of several bioactive
Access to Divergent Fluorinated Enynes and Arenes via Palladium-Catalyzed Ring-Opening Alkynylation of <i>gem</i>-Difluorinated Cyclopropanes
作者:Ebrahim-Alkhalil M. A. Ahmed、Ayman M. Y. Suliman、Tian-Jun Gong、Yao Fu
DOI:10.1021/acs.orglett.0c00022
日期:2020.2.21
Herein, we describe a palladium-catalyzed alkynylation of gem-difluorinated cyclopropanes via C-C bond activation/C-F bond cleavage, followed by C-C(sp) coupling. The new approach proceeds with broad substrate scope under mild reaction conditions, whereas both 1,1-disubstituted and complex-molecule-modified gem-difluorinated cyclopropanes react smoothly with high stereoselectivity. The developed method