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。
Palladium-Catalyzed Direct Approach to α-Trifluoromethyl Alcohols by Selective Hydroxylfluorination of <i>gem</i>
-Difluoroalkenes
作者:Bin Zhang、Xiaofei Zhang、Jian Hao、Chunhao Yang
DOI:10.1002/ejoc.201800468
日期:2018.9.30
A mild and efficient synthesis of α‐trifluoromethyl alcohols derivatives was achieved via Pd‐catalyzed selective hydroxylfluorination of gem‐difluoroalkenes using NFSI as the fluoride source.
salts has rendered the products easily isolable, which greatly improved the synthetic practicality of the monodefluoroborylation reaction. Stoichiometric experiments indicate that the fate of the regioselectivity depends on the mode of β-fluorine elimination, which depends on the substrate. Further transformation of the boryl group has allowed facile preparation of fluoroalkene derivatives as exemplified
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.
Organocatalytic Nucleophilic Substitution Reaction of <i>gem</i>-Difluoroalkenes with Ketene Silyl Acetals
作者:Azusa Kondoh、Kazumi Koda、Masahiro Terada
DOI:10.1021/acs.orglett.9b00566
日期:2019.4.5
An organocatalytic nucleophilic substitution reaction of gem-difluoroalkenes with ketene silyl acetals was developed. Phosphazene P4-tBu effectively catalyzed the reaction under mild conditions to provide monofluoroalkenes possessing an alkoxycarbonylmethyl group in high yields with high Z selectivities.
开发了宝石-二氟烯烃与乙烯酮甲硅烷基缩醛的有机催化亲核取代反应。磷腈P4- t Bu在温和条件下有效催化了该反应,以高收率和高Z选择性提供了具有烷氧羰基甲基的一氟烯烃。