Nucleophilic Vinylic Substitution (S_NV) of Trisubstituted Monofluoroalkenes for the Synthesis of Stereodefined Trisubstituted Alkenes and Divinyl Ethers

Abstract

We herein describe a nucleophilic vinylic substitution (SNV) of trisubstituted monofluoroalkenes with excellent stereocontrol (d.r. > 99:1). Starting from (E)-β-monofluoroacrylates, various trisubstituted (E)-alkenes containing O/N/S-substituent groups at the vinylic position can be obtained under simple conditions. Furthermore, (E,E)-divinyl ethers can be generated through dimerization of the monofluoroalkenes, triggered by adventitious water in the reaction mixture.

Preparation of Vinylphosphonates from Ketones Promoted by Tf2O

“…Additionally, when 5 was heated with triethyl phosphite, a nucleophilic P­(III) species, 3ab was detected (Part B of Scheme ). The results suggest that 5 may be the key intermediate in the reaction and the process may proceed via nucleophilic vinylic substitution. , …”

Synthetic Advantages of Defluorinative C−F Bond Functionalization

“…The polarization of gem ‐difluoroalkenes also promotes nontraditional regioselectivity for cyclization reactions, as evidenced by 5‐ endo‐trig processes studied by Ichikawa and co‐workers to produce diverse fluorinated heterocycles (Scheme 19c) [105] . Similar addition/elimination reactions occur with monofluoroalkenes, although additional activation by electron‐deficient substituents is required [106] …”

“…[105] Similar addition/elimination reactions occur with monofluoroalkenes, although additional activation by electron-deficient substituents is required. [106]…”

A formal vinylic substitution reaction for the synthesis of α,β-unsaturated enol esters and their anticancer potential

“…13 S N V reactions of vinylic fluorides endowed with electron-withdrawing substituents are rather well-explored. 14 However, it may be noted that the methods for the direct formation of a vinylic carbon–oxygen bond via solvolysis of vinylic halides are rare and low-yielding. 15 Other methods available for vinylic carbon–heteroatom bonds generally require the use of expensive metal catalysts.…”