71249-01-9Relevant academic research and scientific papers
Catalyst Effects on Reactions of α,β-Unsaturated Ketones and Esters with Haloforms under Phase-Transfer Catalysis
Dehmlow, Eckehard V.,Wilkenloh, Juergen
, p. 582 - 588 (2007/10/02)
Reactions of acceptor-substituted alkenes with haloform/sodium hydroxide and PT-catalyst result in dihalocarbene additions competitive to Michael additions, with or without consecutive cyclization, and further reactions.Product compositions are strongly dependent on the nature of the phase-transfer catalyst: Sterically unhindered quarternary ammonium ions and benzo-crown ethers favour processes via carbenes, large delocalized (soft) cations foster primary Michael additions.Thus, tert-butyl cis-crotonate is dichlorocyclopropanated stereospecifically with NMe4Cl.The respective stereospecific CBr2 conversion is successful only with PhHgCBr3 .
