A New Route for the Preparation of Substituted 2,2-Difluorostyrenes and a Convenient Route to Substituted (2,2,2-Trifluoroethyl)benzenes
摘要:
The (2,2-difluoroethenyl)zinc reagent II is coupled with aryl iodides or bromides in the presence of Pd(PPh3)(4) in DMF to give the corresponding 2,2-difluorostyrenes IV. The 4-substituted (tetrafluoroaryl)copper reagents are coupled with 2,2-difluoro-1-iodoethylene (I) to produce the corresponding styrene derivatives VII. Both methods provide good yields of the coupled products. These products react with wet KF in DMF or DMSO to form the (2,2,2-trifluoroethyl)benzene derivatives VIII in good yields.
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。
A versatile difluorovinylation method: Cross-coupling reactions of the 2,2-difluorovinylzinc–TMEDA complex with alkenyl, alkynyl, allyl, and benzyl halides
2-difluorovinylzinc–TMEDA complex was prepared via a deprotonation–transmetallation sequence starting from commercially available 1,1-difluoroethylene. The complex thus formed was successfully applied to transition metal-catalyzed cross-coupling reactions with a wide range of organic halides, which led to the syntheses of 2,2-difluorovinyl compounds. On treatment with the difluorovinylzinc–TMEDA complex in the presence
Metal-Free Access to (<i>E/Z</i>
)-α-Fluorovinyl Phosphorus Compounds from <i>gem</i>
-Difluorostyrenes
作者:Yingyuan Peng、Xiaofei Zhang、Xueyu Qi、Qian He、Bin Zhang、Jian Hao、Chunhao Yang
DOI:10.1002/ejoc.201801602
日期:2019.2.7
A facile and efficient method to synthesize (E/Z)‐α‐fluorovinyl phosphorus compounds from gem‐difluorostyrenes and diphenylphosphine oxide/dialkyl phosphate in the presence of DBU at room temperature was developed. This method may provide a practical and concise route for the synthesis of these phosphorus compounds in material chemistry and drug discovery in the future.
which otherwise are essentially reluctant towards F‐nucleoplilic addition, now readily participate in this fluoroallylation reaction. Furthermore, this strategy provides an elegant example for the generation, as well as functionalization, of α‐CF3‐substituted benzylic radical intermediates using cheap and readily available starting materials.
Direct Difluoromethylenation of Carbonyl Compounds by Using TMSCF<sub>3</sub>: The Right Conditions
作者:Sankarganesh Krishnamoorthy、Jotheeswari Kothandaraman、Jacqueline Saldana、G. K. Surya Prakash
DOI:10.1002/ejoc.201601038
日期:2016.10
A deoxygenative difluoromethylenation of carbonylcompounds has been developed by using readily available, inexpensive trifluoromethyltrimethylsilane, LiI, and PPh3. The presence of the Li+ ion prevents the unproductive exhaustion of trifluoromethyltrimethylsilane (TMSCF3) by keeping the soluble free fluoride concentration in the reaction medium under control. The strategy of combining solvents to