A three-membered ring approach to carbonyl olefination. Issue 1 (December 2017) - Niyomchon, Supaporn
Abstract The carbon–carbon double bond, with its diverse and multifaceted reactivity, occupies a prominent position in organic synthesis. Although a variety of simple alkenes are readily available, the mild and chemoselective introduction of a unit of unsaturation into a functionalized organic molecule remains an ongoing area of research, and the olefination of carbonyl compounds is a cornerstone of such approaches. Here we show the direct olefination of hydrazones via the intermediacy of three-membered ring species generated by addition of sulfoxonium ylides, departing from the general dogma of alkenes synthesis from carbonyls. Moreover, the mild reaction conditions and operational simplicity of the transformation render the methodology appealing from a practical point of view. Alkenes are versatile buildings blocks in organic synthesis. Here, the authors developed a three-membered ring strategy to access a variety of functionalized alkenes by coupling of in-situ generated azines with sulfoxonium ylides.