118993-93-4Relevant articles and documents
Intermolecular metal-free cyclopropanation of alkenes using tosylhydrazones
Barluenga, Jose,Quinones, Noelia,Tomas-Gamasa, Maria,Cabal, Maria-Paz
supporting information; experimental part, p. 2312 - 2317 (2012/06/01)
We describe the first general method for the metal-free cyclopropanation of alkenes by using N-tosylhydrazones as an in situ source of diazo compounds. This new method works with a wide variety of alkenes (styrene derivatives, dienes, enynes, and electron-deficient alkenes) by using N-tosylhydrazones derived from various ketones or aldehydes (aromatic, aliphatic, enones). The reaction is performed with the use of K2CO3 as a base to form the diazo species and is compatible with a wide array of functional groups. A new procedure for the synthesis of cyclopropanes by the formal cyclopropanation of carbonyl compounds and alkenes is described. This metal-free reaction proceeds through the base-promoted decomposition of tosylhydrazones. There is significant tolerance of the functional groups, enabling cyclopropanation in the presence of functionalities often not compatible with other methodologies.