1,1-Disubstituted vinyl triflates are synthesized by direct hydrotriflation of terminal alkynes employing a combination of TfOH and TMSN3 in DCM at room temperature. Interestingly, under these conditions, only terminal alkynes were selectively converted to the corresponding vinyl triflates, while internal alkynes were not reacted. A broad range of substrates were successfully converted to the corresponding
Photoredox- or Metal-Catalyzed in Situ SO<sub>2</sub>-Capture Reactions: Synthesis of β-Ketosulfones and Allylsulfones
作者:Min Zheng、Guigen Li、Hongjian Lu
DOI:10.1021/acs.orglett.9b00201
日期:2019.2.15
as radical acceptors and SO2 sources to provide various β-ketosulfones and allylsulfones, known to be significant building blocks. Without the use of any additives including external SO2 gas, the reaction was performed under mild photoredox- or metal-catalytic conditions while tolerating various functional groups.
Synthesis of α‐Trifluoromethylated Ketones from Vinyl Triflates in the Absence of External Trifluoromethyl Sources
作者:Takuji Kawamoto、Rio Sasaki、Akio Kamimura
DOI:10.1002/anie.201608591
日期:2017.1.24
A novel method for the conversion of vinyl triflates into α‐trifluoromethylated ketones in the absence of external trifluoromethyl sources is described. This process accomplishes an efficient migration of the trifluoromethyl group of the triflate to the α‐position in the ketone through a radical process. The reaction proceeds by the addition of a trifluoromethyl radical to the vinyl triflate and subsequent
Facile Synthesis of α-N-Heterocyclic Carbene-Boryl Ketones from N-Heterocyclic Carbene-Boranes and Alkenyl Triflates
作者:Wen Dai、Steven J. Geib、Dennis P. Curran
DOI:10.1021/jacs.9b05547
日期:2019.8.7
experimental evidence supports a radical chain mechanism that involves: (1) addition of an NHC-boryl radical to the alkenyl triflate, (2) fragmentation to give the α-NHC-boryl ketone, SO2 and trifluoromethylradical, and (3) hydrogenabstraction by trifluoromethylradicalfrom the starting NHC-borane to return the NHC-boryl radical along with trifluoromethane. Reactions (1) and (3) are both new and evidently