Base Catalysis Enables Access to α,α-Difluoroalkylthioethers
作者:Douglas L. Orsi、Brandon J. Easley、Ashley M. Lick、Ryan A. Altman
DOI:10.1021/acs.orglett.7b00386
日期:2017.4.7
A nucleophilicaddition reaction of aryl thiols to readily available β,β-difluorostyrenes provides α,α-difluoroalkylthioethers. The reaction proceeds through an unstable anionic intermediate, prone to eliminate fluoride and generate α-fluorovinylthioethers. However, the use of base catalysis overcomes the facile β-fluoride elimination, generating α,α-difluoroalkylthioethers in excellent yields and
Direct Difluoromethylenation of Carbonyl Compounds by Using TMSCF<sub>3</sub>: The Right Conditions
作者:Sankarganesh Krishnamoorthy、Jotheeswari Kothandaraman、Jacqueline Saldana、G. K. Surya Prakash
DOI:10.1002/ejoc.201601038
日期:2016.10
A deoxygenative difluoromethylenation of carbonylcompounds has been developed by using readily available, inexpensive trifluoromethyltrimethylsilane, LiI, and PPh3. The presence of the Li+ ion prevents the unproductive exhaustion of trifluoromethyltrimethylsilane (TMSCF3) by keeping the soluble free fluoride concentration in the reaction medium under control. The strategy of combining solvents to
Synthesis of Exocyclic Trisubstituted Alkenes
<i>via</i>
Nickel‐ Catalyzed Kumada‐Type Cross‐Coupling Reaction of
<i>gem</i>
‐ Difluoroalkenes with Di‐Grignard Reagents
作者:Wenpeng Dai、Xuxue Zhang、Juan Zhang、Yingyin Lin、Song Cao
DOI:10.1002/adsc.201500889
日期:2016.1.21
A practical, nickel‐catalyzed Kumada‐type double cross‐coupling reaction of gem‐difluoroalkenes with 1,4‐ or 1,5‐di‐Grignard reagents was developed. The reaction proceeded efficiently at room temperature and a variety of cyclization products, arylmethylenecyclopentanes and arylmethylenecyclohexanes, were obtained in high to excellent yields, respectively.
A key intermediate, difluoromethylene phosphobetaine, in the Wittig reaction of ClCF2CO2Na–Ph3P with aldehydes was synthesized and characterized, which confirmed the reaction mechanism. The decarboxylation of this stable intermediate was a convenient approach for Wittig difluroolefination. Its reactivity could be adjusted by the modification of the substituent on the phosphorus.
Difluoromethyl 2-Pyridyl Sulfone: A New <i>gem-</i>Difluoroolefination Reagent for Aldehydes and Ketones
作者:Yanchuan Zhao、Weizhou Huang、Lingui Zhu、Jinbo Hu
DOI:10.1021/ol100090r
日期:2010.4.2
Difluoromethyl2-pyridylsulfone, a previously unknown compound, was found to act as a novel and efficient gem-difluoroolefination reagent for both aldehydes and ketones. It was found that the fluorinated sulfinate intermediate in the reaction is relatively stable, which can be observed by 19F NMR and trapped with CH3I.
发现二氟甲基2-吡啶基砜(一种以前未知的化合物)可同时作为醛和酮的新型高效二氟烯烃聚合试剂。发现反应中的氟化亚磺酸盐中间体相对稳定,这可以通过19 F NMR观察到并被CH 3 I捕获。