Alkyltriflones in the Ramberg–Bäcklund Reaction: An Efficient and Modular Synthesis of <i>gem</i>-Difluoroalkenes
作者:Yuuki Maekawa、Masakazu Nambo、Daisuke Yokogawa、Cathleen M. Crudden
DOI:10.1021/jacs.0c07924
日期:2020.9.16
of gem-difluoroalkenes through the Ramberg-Bäcklund reaction of alkyl triflones is described herein. Structurally diverse, fully-substituted gem-difluoroalkenes that are difficult to prepare by other methods can be easily prepared from readily available triflones by treatment with specific Grignard reagents. Experimental and computationalstudies provide insight into the unique and critical role of
Base promoted <i>gem</i>-difluoroolefination of alkyl triflones
作者:Ren-Yin Yang、Hui Wang、Bo Xu
DOI:10.1039/d1cc01132d
日期:——
A new synthesis of gem-difluoroalkenes from readily available alkyl triflones and difluorocarbene precursors such as TMSCF2Br has been reported. The reaction, regardless of electronic effect, gives gem-difluoroalkenes in good to excellent yields. The mechanism may involve deprotonation of triflones, nucleophilic addition, and the elimination of SO2CF3.
A novel strategy is demonstrated for Lewis base-activated trifluoromethylsulfinylation of allylic alcohols. Controllable synthesis of structurally varied allylic trifluoromethanesulfones via sigmatropic rearrangements was performed, and trifluoromethanesulfinate esters were achieved. This metal-free, catalytic divergent transformation features good functional group tolerance and late-stage modification
A general and convenient copper-mediated trifluoromethylthiolation of primary and secondary alkyl halides was described. Variation of the solvent, additives and time allowed optimization of the reaction. A wide range of alkyl halides were explored to give a set of alkyl trifluoromethyl thioethers in moderate to excellent yields. A variety of functional groups, including ethers, thioether, esters, nitriles, amides, and ketal groups, were well tolerated in the electrophilic partner.
A Protocol To Transform Sulfones into Nitrones and Aldehydes
作者:Eduardo Rodrigo、Inés Alonso、M. Belén Cid
DOI:10.1021/acs.orglett.8b02483
日期:2018.9.21
A simple method to transform sulfones into nitrones and therefore into the corresponding carbonyl derivatives has been developed. Some examples demonstrate that it is a new reliable and versatile reaction in the toolbox of sulfones that has great synthetic potential. NMR and computational studies were used to elucidate the mechanism.