Hydrosulfonylation Reaction with Arenesulfonyl Chlorides and Tetrahydrofuran: Conversion of Terminal Alkynes into Cyclopentylmethyl Sulfones

Abstract

An efficient and simple radical chain reaction to convert terminal alkynes into arenesulfonylmethylcyclopentanes is described. The reaction involves a radical addition-translocation-cyclization process and necessitates solely the use of readily available arenesulfonyl chlorides in tetrahydrofuran. Interestingly, this radical-mediated C-H activation process took place with a high level of retention of configuration when an enantiomerically pure starting material was used.

Palladium‐Catalyzed Atom‐Transfer Radical Cyclization at Remote Unactivated C(sp3)−H Sites: Hydrogen‐Atom Transfer of Hybrid Vinyl Palladium Radical Intermediates

“…[4] Based on the ability of these hybrid palladium radical species to activate CÀHb onds by aHAT process,wewere eager to investigate the possibility of achieving aHAT process with vinyl hybrid palladium radical intermediates as ap latform for development of new transformations.T othe best of our knowledge,there have been no reports on the generation and reactivity of vinyl hybrid palladium radical intermediates. [5] Herein, we report am ild, visible-light-induced exogenous photosensitizer free [6,7] formation of novel hybrid vinyl palladium radical species which trigger aH AT process at unactivated C(sp 3 )ÀHs ites [8] /nonchain atom-transfer radical cyclization sequence to produce valuable iodoalkyl carbo-and heterocycles (Scheme 1c).…”

Visible‐Light‐Mediated Chlorosulfonylative Cyclizations of 1,6‐Enynes

“…Alternatively, a radical chain process involving the direct chlorination of carbon radicals 8 and 11 by TsCl to generate 3 and 5 is also possible …”

“…Alternatively, a radical chain process involving the direct chlorination of carbon radicals 8 and 11 by TsCl to generate 3 and 5 is also possible. [22] Notably, only exo-trig cyclization products were formed and isolated in all reactions. This selectivity is probably due to the geometric and stereoelectronic properties of the enynes.…”

Merging Art and Science—The 53rd Bürgenstock Conference

“…The evening lecture was given by Philippe Renaud (University of Bern) who introduced us to his vision on how to tackle challenges in radical chemistry. He presented several exciting strategies based on radical generation, such as chlorosulfonylation of dienes for the formation of five‐membered rings, fluorination with organoboranes, smooth radical‐promoted reduction with catecholboranes, deuterative deiodination reaction with D 2 O, or concepts for repairing the thiol–ene coupling reaction. The epilogue of his presentation disclosed the hydroalkoxylation of substituted alkenes by means of a radical chain process.…”