A method that allows for the reduction of protected hydroperoxides by employing catalytic amounts of phosphine is presented. The combination of a titanium(IV) alkoxide and a siloxane allowed for the chemoselective reduction of phosphine oxides in the presence of alkyl silyl peroxides. Subsequent reduction of the peroxide moiety by phosphine provided the corresponding silylated alcohols in useful yields. Mechanistic experiments, including crossover experiments, support a mechanism in which the peroxide group was reduced and the silyl group was transferred in a concerted step. Labeling studies with (17)O-labeled peroxides demonstrate that the oxygen atom adjacent to the silicon atom is removed from the silyl peroxide.

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An efficient four-step synthesis of N-BOC-5-syn- and 5-anti-carboxymethanopyrrolidines (12 and 13) and the conversion of 12 to N-BOC-methanopyrrolidine (2) are described.

Treatment of γ,δ-unsaturated ketones with hydrogen peroxide and acid provides a rapid entry into the medicinally important 1,2,4-trioxane structure. Alkene substitution that stabilizes carbocationic intermediates proved to be important for the success of this transformation.