The utilization of economic and practical trifluoromethyl reagents to introduce trifluoromethyl(CF_(3))groups into organic molecules is an important research focus due to their role as vital structuralmotifs in the ph...The utilization of economic and practical trifluoromethyl reagents to introduce trifluoromethyl(CF_(3))groups into organic molecules is an important research focus due to their role as vital structuralmotifs in the pharmaceutical and agricultural industries.Herein,we disclose a cost-efficient and practical approach of photoinduction of a radical relay process for the synthesis ofα-CF_(3)ketones.We showed that trifluoromethylation reagents such as TES-OTf,Tf2O,TMS-OTf,TBS-OTf,H-OTf,and others,could be used successfully as inexpensive CF_(3)precursors under metal-free and redox-neutral conditions.The potential application of this protocol was highlighted further by late-state modification of drug segments and gram-scale synthesis.Our mechanistic studies revealed that this transformation might involve a radical process,and acetic acid(CH3COOH)not only promoted the formation of enol triflates,but also accelerated the in situ conversion from enol triflates toα-CF_(3)ketones.展开更多
Degradation of the highly reactive hypervalent trifluoromethylation iodine reagent PhI（OAc）（CF3）, which can only be generated in situ with mixing PhI（OAc）2 and TMSCF3 in the presence of CsF, was studied by ESI-M...Degradation of the highly reactive hypervalent trifluoromethylation iodine reagent PhI（OAc）（CF3）, which can only be generated in situ with mixing PhI（OAc）2 and TMSCF3 in the presence of CsF, was studied by ESI-MS and GC-MS combined with ~9F-NMR. The important transient intermediate PhlCF3＋ was determined by ESI-MS, and the major volatile products containing CF3 were identified with the authentic compounds by using GC-MS, such as trifluoromethylbenzene, 2-iodobenzotrifluoride, 3-iodobenzotrifluoride, 4-iodobenzotrifluoride. Meanwhile, more evidences obtained with 19F-NMR were given for such degradation reaction. A possible rapid CF3 radical transfer reaction pathway was proposed to clarify such degradation progress based on the experimental results. Therefore, this study may be helpful in elucidating the intrinsic reactivity of PhI（OAc）（CF3） and the possible competing side reactions caused by such self-degradation pathway.展开更多
基金This work was supported by the National Natural Science Foundation of China(nos.21390402 and 21520102003)the Hubei Province Natural Science Foundation of China(no.2017CFA010)The Program of Introducing Talents of Discipline to Universities of China(111 Program)is also appreciated.
文摘The utilization of economic and practical trifluoromethyl reagents to introduce trifluoromethyl(CF_(3))groups into organic molecules is an important research focus due to their role as vital structuralmotifs in the pharmaceutical and agricultural industries.Herein,we disclose a cost-efficient and practical approach of photoinduction of a radical relay process for the synthesis ofα-CF_(3)ketones.We showed that trifluoromethylation reagents such as TES-OTf,Tf2O,TMS-OTf,TBS-OTf,H-OTf,and others,could be used successfully as inexpensive CF_(3)precursors under metal-free and redox-neutral conditions.The potential application of this protocol was highlighted further by late-state modification of drug segments and gram-scale synthesis.Our mechanistic studies revealed that this transformation might involve a radical process,and acetic acid(CH3COOH)not only promoted the formation of enol triflates,but also accelerated the in situ conversion from enol triflates toα-CF_(3)ketones.
基金The authors are grateful for financial supports from the National Natural Science Foundation of China （NSFC Grant Nos. 21475145 and 21472228） and Youth Innovation Promotion Association CAS （201317 !）.
文摘Degradation of the highly reactive hypervalent trifluoromethylation iodine reagent PhI（OAc）（CF3）, which can only be generated in situ with mixing PhI（OAc）2 and TMSCF3 in the presence of CsF, was studied by ESI-MS and GC-MS combined with ~9F-NMR. The important transient intermediate PhlCF3＋ was determined by ESI-MS, and the major volatile products containing CF3 were identified with the authentic compounds by using GC-MS, such as trifluoromethylbenzene, 2-iodobenzotrifluoride, 3-iodobenzotrifluoride, 4-iodobenzotrifluoride. Meanwhile, more evidences obtained with 19F-NMR were given for such degradation reaction. A possible rapid CF3 radical transfer reaction pathway was proposed to clarify such degradation progress based on the experimental results. Therefore, this study may be helpful in elucidating the intrinsic reactivity of PhI（OAc）（CF3） and the possible competing side reactions caused by such self-degradation pathway.
