Coupling of 2-Substituted 1-Fluorovinylstannanes with Organic Halides Catalyzed by Palladium(0)/Copper(I) Iodide. A Mild and Stereospecific Method to Monofluoroolefins

Abstract

The palladium-catalyzed cross-coupling reactions of (E)- or (Z)-1-fluorovinylstannanes with aryl iodides and vinyl iodides provide good yields of stereoisomerically pure substituted fluoroolefins with retention of the double bond geometry. The reaction takes place with copper(I) iodide present as a cocatalyst at ambient temperature or in refluxing tetrahydrofuran and is tolerant of a variety of functional groups. Highly functionalized and stereoisomerically pure monofluorovinyl ketones also were obtained under mild conditions by the coupling of 1-fluorovinylstannanes with acid chlorides. (1)H-{(19)F} NOE NMR experiments unequivocally established the stereochemistry of the coupling products E-14 and Z-14.

Stille cross-coupling reaction of polyfluorovinylstannanes

“…The Stille cross coupling reaction of fluorinated vinylstannanes has been reported with retention of configuration [28][29][30], in our studies, the retentation of configuration was observed similarly on the basis of their 4 J FF coupling constant. It can be seen from the Table 1 that the yield of the reaction of aryl iodide with an electron-donating group was lower (compound 3b) being similarly as compared with the result reported in the literature [28]. However, there is no apparent effect on the yields of products when an electron-donating group is located in the R group of vinylstannanes 1 (compounds 3d and 3e).…”

“…The lower reactivity of fluorinated vinylstannanes [28][29][30] as compared with the corresponding nonfluorinated vinylstannanes is obviously due to its strong electron-withdrawing effect of fluorine. Thus, the addition of CuI as cocatalyst [32] is necessary.…”

“…The Stille crosscoupling reaction, which is a widely employed method for the carbon-carbon bond formation [15][16][17][18], has recently become a popular synthetic tool in organic synthesis, particularly for the synthesis of naturally occurring compounds [19][20][21][22][23][24][25][26][27]. Recently 1-fluorovinylstannanes [28], 1,2-difluorovinylstannanes [14,29], and trifluoromethylvinylstannanes [30] as coupling partners in Stille cross-coupling reaction have been reported. However, the use of polyfluorovinylstannanes as coupling partner in Stille cross-coupling reaction has not been reported previously.…”

Regiospecific synthesis of symmetrical (1E,3E) 2,3-difluoro-1,4-diphenyl-buta-1,3-dienes via palladium-catalyzed cross-coupling of (Z) 2-bromo-2-fluoroethenylbenzenes in presence of bis(pinacolato)diboron

“…1 H NMR (300 Mhz, CDCl 3 ) d: 6.54 (2H, dd, 3 J FH ¼ 10:85 Hz, 4 J FH ¼ 5:96 Hz), 7.19 (10H, broad s). 13 …”

“…Popular methodologies for the preparation of fluorinated olefins or dienes involve palladium catalyzed coupling reaction between 1-fluorovinyl halides with terminal alkynes, organoboranes or organostannanes [11][12][13][14], or palladium-catalyzed coupling reaction of fluorinated organometallics (fluorinated organozinc, fluorinated stannanes, fluorinated copper) with organic halides [15][16][17]. These methodologies are compatible with easily cleavable protecting groups and allow the synthesis of functionalized natural products as demonstrated by the straightforward access to fluororesveratrol [18].…”