Nucleophilic (phenylsulfonyl)difluoromethylation of alkyl halides using PhSO2CF2SiMe3: preparation of gem-difluoroalkenes and trifluoromethyl compounds
摘要:
Nucleophilic (phenylsulfonyl)difluoromethylation of both alkyl iodides and bromides was successfully accomplished by using CsF/15-crown-5 as an initiating system in DME, and the amount of 15-crown-5 was found to be critical to the yield of the product. The prepared (phenylsulfonyl)difluoromethylated alkanes were converted into gem-difluoroalkenes by a base-mediated 1,2-elimination reaction, and the latter species could be further transformed into trifluoromethyl compounds in the presence of KF/18-crown-6 or TBAF. (C) 2010 Elsevier Ltd. All rights reserved.
[3 + 2]-Annulation of <i>gem</i>-Difluoroalkenes and Pyridinium Ylides: Access to Functionalized 2-Fluoroindolizines
作者:Jun-Qi Zhang、Dandan Hu、Jinyu Song、Hongjun Ren
DOI:10.1021/acs.joc.0c03041
日期:2021.3.19
A [3 + 2]-annulation of gem-difluoroalkenes and pyridinium ylides was developed employing ambient air as the sole oxidant in an open-vessel manner, affording a series of multifunctionalized 2-fluoroindolizines in moderate to good yields. In this reaction, gem-difluoroalkene acts as a C2 synthon and entirely avoids the competitive addition–elimination process, which provides facile access to 2-fluoroindolizines
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
Regioselective Radical Hydroboration of <i>gem</i>-Difluoroalkenes: Synthesis of α-Borylated Organofluorines
作者:Ji-Kang Jin、Wan-Xin Zheng、Hui-Min Xia、Feng-Lian Zhang、Yi-Feng Wang
DOI:10.1021/acs.orglett.9b03173
日期:2019.10.18
hydroboration of gem-difluoroalkenes was developed for the synthesis of α-difluoroalkylborons. The reaction features excellent regioselectivity, broad substrate scope, and good functional group capability. DFT calculations implicated the remarkable α-selectivity was driven from the kinetically and thermodynamically more favorable α-addition step. The resulting α-difluoroalkylborons could be readily converted
reported. By taking advantage of the in situ generated α-CF3-benzylsilver intermediates derivedfrom the nucleophilic addition of silver fluoride to gem-difluoroalkenes, this strategy bypasses the use of a strong base, thus enabling a mild and general synthetic method for ready access to non-symmetric α,α-disubstituted trifluoroethane derivatives.
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.