Diastereoselective Radical‐Mediated Hydrogen‐Atom Abstraction

Thiophenol‐Mediated 1,5‐Hydrogen Atom Abstraction: Easy Access to Mono‐ and Bicyclic Compounds

“…Expeditious preparation of fused-ring and spirocyclic compounds illustrates the potential of this approach and complements our preliminary results reported recently. [24,25]…”

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

“…Theu se of sulfonyl hydrazides [10] and sulfinates [11] under oxidative conditions has also been reported. [13,14] Ther eaction was observed for the first time during an attempt to form ac yclopentane derivative through chlorosulfonylation of alkyne 1a with para-toluenesulfonyl chloride and dilauroyl peroxide (DLP) in cyclohexane at reflux (Scheme 2). [12] We report herein ah ydrosulfonylation procedure based on the use of commercially or readily available arenesulfonyl chlorides and THF as the source of the hydrogen atom, thus avoiding the use of any dedicated reducing agent.…”

“…The reaction has been used to carry out efficient cascade reactions involving ar adical addition-translocation-cyclization (RATC) process leading to the formation of aryl cyclopentylmethyl sulfones from terminal alkynes. [13,14] Ther eaction was observed for the first time during an attempt to form ac yclopentane derivative through chlorosulfonylation of alkyne 1a with para-toluenesulfonyl chloride and dilauroyl peroxide (DLP) in cyclohexane at reflux (Scheme 2). In contrast to previously reported radical cascades involving the cyclization of dienes [6a,i, 11a, 15] and enynes [10c, 16] or ring opening of vinylcyclopropanes, [17] no trace of the expected cyclic chlorinated sulfone 3a was observed.…”

From Palladium to Brønsted Acid Catalysis: Highly Enantioselective Regiodivergent Addition of Alkoxyallenes to Pyrazolones

“…[3] Despite the blossoming of asymmetric catalysis over the last few decades,t he development of such strategy is still in demand, yet remains af ormidable challenge.P yrazol-5-ones are an important family of five-membered heterocycles which have been known for more than one century and have been studied because of the broad application in drug chemistry. [7][8][9][10] Mechanistically,t he generation of ap alladium(II) hydride intermediate by oxidative addition of an ucleophile to the precatalyst palladium(0) complex triggers the reaction, with subsequent hydropalladation of an allene to form an analogous Pd(p-allyl) intermediate which proceeds to the catalytic transformation. [5c-e] As aresult, efficient assembly of afamily of such enantiopure multifunctionalized heterocyclic compounds would be of great importance,y et remains challenging.…”

“…[7][8][9][10] Mechanistically,t he generation of ap alladium(II) hydride intermediate by oxidative addition of an ucleophile to the precatalyst palladium(0) complex triggers the reaction, with subsequent hydropalladation of an allene to form an analogous Pd(p-allyl) intermediate which proceeds to the catalytic transformation. [7][8][9][10] Mechanistically,t he generation of ap alladium(II) hydride intermediate by oxidative addition of an ucleophile to the precatalyst palladium(0) complex triggers the reaction, with subsequent hydropalladation of an allene to form an analogous Pd(p-allyl) intermediate which proceeds to the catalytic transformation.…”