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.

The effects of memory of chirality (MoC) in reactions involving monoradical species are reviewed here. Reactions involving a nonracemic chiral starting material bearing a single stereogenic element such as a chiral center or chiral axis directly involved in the new bond formation are discussed. These reactions lead to a nonracemic product via an intermediate susceptible to rapid racemization. Memory of chirality has been observed in cyclic radicals, aryl, ester/amide substituted acyclic radicals, and benzylic radicals at temperatures up to 130 °C.

An efficient and simple radical chain reaction to convert terminal alkynes into arenesulfonylmethylcyclopentanes is described. The reaction involves ar adical additiontranslocation-cyclization process and necessitates solely the use of readily available arenesulfonyl chlorides in tetrahydrofuran. Interestingly,t his radical-mediated C À Ha ctivation process took place with ah igh level of retention of configuration when an enantiomerically pure starting material was used.Scheme 1. Ac yclopentylmethyl phenyl sulfone building block.Scheme 2. Discovery of the hydrosulfonylation reaction. Tol = tolyl.

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