A silicon‐assisted synthesis of (E)‐β‐haloenamides from N‐vinylamides

Abstract

E)-β-Iodoenamides and (E)-β-iodoenimides can be easily obtained from N-vinyl derivatives (N-vinylamides and N-vinylimides) by stereoselective ruthenium-catalysed silylative coupling with vinyltrimethylsilane (Marciniec coupling) and subsequent stereospecific silicon-iodine exchange. Bromodesilylation of (E)-β-silylenimides affords (E)-β-bromoenimides, while the analogous reactions involving (E)-β-silylenamides lead to decomposition of substrates. N-Halosuccinimides have been found as the most effective halogenating agents in the desilylation step under mild conditions. The ruthenium-catalysed silylation/halodesilylation sequence can be performed in a one-pot procedure.

Silylative coupling of olefins with vinylsilanes in the synthesis of functionalized alkenes

“…[36][37][38][39] The study has been concentrated on the search for new direct and selective methods for the syntheses of functionalized (E)-alkenyl halides from terminal alkenes with the use of certain products of sequential reactions in selected catalytic processes (e.g. [36][37][38][39] The study has been concentrated on the search for new direct and selective methods for the syntheses of functionalized (E)-alkenyl halides from terminal alkenes with the use of certain products of sequential reactions in selected catalytic processes (e.g.…”

“…38,39 A series of (E)-β-iodoenamides and (E)-β-iodoenimides has been easily obtained from N-vinyl derivatives (Nvinylamides and N-vinylimides) by stereoselective [Ru(H)(Cl)-(CO)(PCy 3 ) 2 ]-catalyzed silylative coupling with vinyltrimethylsilane and subsequent stereospecific silicon-iodine exchange mediated by N-iodosuccinimide or molecular iodine under mild conditions (Scheme 5). 38,39 A series of (E)-β-iodoenamides and (E)-β-iodoenimides has been easily obtained from N-vinyl derivatives (Nvinylamides and N-vinylimides) by stereoselective [Ru(H)(Cl)-(CO)(PCy 3 ) 2 ]-catalyzed silylative coupling with vinyltrimethylsilane and subsequent stereospecific silicon-iodine exchange mediated by N-iodosuccinimide or molecular iodine under mild conditions (Scheme 5).…”

“…38,39 A series of (E)-β-iodoenamides and (E)-β-iodoenimides has been easily obtained from N-vinyl derivatives (Nvinylamides and N-vinylimides) by stereoselective [Ru(H)(Cl)-(CO)(PCy 3 ) 2 ]-catalyzed silylative coupling with vinyltrimethylsilane and subsequent stereospecific silicon-iodine exchange mediated by N-iodosuccinimide or molecular iodine under mild conditions (Scheme 5). 38 The ruthenium-catalyzed silylation/halodesilylation sequence can be also performed in a one-pot procedure without the isolation of silylenamide derivatives to give (E)-β-haloenamides in moderate to good yields (68-88%). 38 The ruthenium-catalyzed silylation/halodesilylation sequence can be also performed in a one-pot procedure without the isolation of silylenamide derivatives to give (E)-β-haloenamides in moderate to good yields (68-88%).…”

“…38,39 Bromodesilylation of (E)-β-silylenimides affords (E)-β-bromoenimides, while the analogous reactions involving (E)-βsilylenamides led to decomposition of substrates. 38 β-Haloenamides are synthetically versatile variants of enamides, offering rapid access to β-metalated enamides that can serve as acyl anion equivalents or can be involved in transition metal-catalyzed reactions. 38 β-Haloenamides are synthetically versatile variants of enamides, offering rapid access to β-metalated enamides that can serve as acyl anion equivalents or can be involved in transition metal-catalyzed reactions.…”

“…The combination of the ruthenium-catalyzed silylative coupling with electrophilic halodesilylation reaction has been used for the stereoselective preparation of synthetically useful (E)alkenyl halides from terminal olefins. [36][37][38][39] The study has been concentrated on the search for new direct and selective methods for the syntheses of functionalized (E)-alkenyl halides from terminal alkenes with the use of certain products of sequential reactions in selected catalytic processes (e.g. Suzuki-Miyaura and Sonogashira coupling reactions) in order to obtain more complex functionalized organic compounds containing π-conjugated systems of double or triple bonds.…”