A Cossy 5-exo-dig photocyclization of organohalides (X = Br, I) onto a C–C triple bond was studied using a flow photomicroreactor, which proceeded in a minute order of residence time. A deuterium labeling study supported the nonchain radical mechanism proposed by the Cossy group, in which a hydrogen source originates from a triethylamine cation radical. Scalable flow synthesis using a larger volume
Titanocene(III) mediated radical cyclization of α-bromo carbonyl compounds: synthesis of tri-substituted tetrahydrofurans
作者:Samaresh Jana、Chandrani Guin、Subhas Chandra Roy
DOI:10.1016/j.tetlet.2004.12.079
日期:2005.2
has been developed for the construction of synthetically important tri-substituted tetrahydrofuran derivatives from bromo-alkenes and bromo-alkynes by radicalcyclization reactions using the radical initiator Cp2TiCl, generated in situ from commercially available titanocene dichloride and Zn dust in tetrahydrofuran under argon.
Stereoselective radical annulation route to the synthesis of (±)-paulownin and (±)-isogmelinol
作者:Sankar Adhikari、Subhas Roy
DOI:10.1016/s0040-4039(00)61118-8
日期:1992.9
A highly stereocontrolled synthesis of (+/-)-paulownin (1a) and (+/-)-isogmelinol (1b) is reported involving intramolecular radical cyclisation reaction as a key step.
Indium(I) iodide as a radical initiator: intramolecular cyclization of functionalized bromo-alkynes to substituted tetrahydrofurans
作者:Brindaban C. Ranu、Tanmay Mandal
DOI:10.1016/j.tetlet.2006.02.135
日期:2006.4
Aryl substituted alpha-carbonyl brorno-alkynes undergo facile cyclizations to the corresponding substituted 4-methylene-tetra-hydrofurans using indium(I) iodide in acetonitrile under sonication in high yields. The reaction is predicted to proceed via a radical process initiated by InI and a plausible radical pathway is suggested. (c) 2006 Elsevier Ltd. All rights reserved.