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5-hydroxy-1-oxo-5?-cholestan-3?-yl acetate (11) was prepared in 5 steps starting from (E)-3?-acetoxy-5,10-seco-1(10)-cholesten-5-one (6). Treatment of the 1-oxo-5-hydroxy derivative 11 with lead tetraacetate (LTA) (under thermal or hypoiodite conditions) or with mercuric oxide/iodine (HgO/I2) reagent resulted in the oxidative ?-fragmentation of the C(5)?C(10) bond affording 1,5-dioxo-5,10-secocholest-10(19)-en-3?-yl acetate (12), in different yields, depending on the reagent. Also the stereochemistry of the 1?,6?-cyclization product 13, formed by transannular cyclization of the 1,5-diketone 12 on silica gel, is discussed in this work.

This review provides an overview of the recent progress made in the area of free-radical additions across the ?-system of olefins, with a focus on the role of sulfonyl derivatives as one of the reaction partners in multicomponent processes. The mechanism and utility in organic synthesis of carbo-alkenylation, alkynylation, oximation and azidation of olefins are thus discussed and illustrated with some applications in total synthesis of natural products.

The decomposition of primary, secondary and tertiary alkyl hypochlorites induced by ferrous and other one-electron oxidizable metal ions leads to δ-chloro alcohols in yields of 34–76%. In decomposition of tertiary alkyl hypochlorites, β-fragmentation competes with intramolecular δ-chlorination. Tertiary cycloalkyl hypochlorites containing five- or six-membered rings undergo β-cleavage giving the corresponding ω-chloro ketones, while 1-methylcycloheptyl and 1-methylcyclooctyl hypochlorites by decomposition with ferrous ion proceed by transannular functionalization of δ-carbon atom and β-cleavage as a competing reaction.