201793-70-6Relevant academic research and scientific papers
Stereoselective preparation of (Z)-α,β-difluorostyrenes and stereospecific conversion to (E)-α,β-difluoro-β-iodostyrenes
Davis,Burton
, p. 9217 - 9222 (1997)
Substituted aromatic iodides coupled with (E)-HFC=CFZnI (E:Z 95.5) under mild conditions, in the presence of catalytic Pd(PPh3)4, in DMF to give (Z)-α,β-difluorostyrenes in good yields. The coupling reaction was tolerant of a variety of functionalities. Isomerically pure (Z)-α,β-difluorostyrenes were readily converted to the corresponding (E)-α,β-difluoro-β- iodostyrenes in good yields by two methods; in one method, treatment of the (Z)-α,β-difluorostyrenes with LTMP at low-temperature gave vinyllithium reagents which were captured in situ with Bu3SnCl to form vinylstannanes. The intermediate vinylstannanes could be isolated or treated directly with I2 to give (E)-α,β-difluoro-β-iodostyrenes in a one-flask procedure. In a second approach, n-BuLi was utilized to pregenerate vinyllithium reagents which were quenched with I2 to afford (E)-α,β-difluoro-β-iodostyrenes.
