Peroxycarbenium ions

SCHEME 34. New dialkyl peroxides via addition of nucleophiles to peroxycarbenium ions... 

Triethysilyl-protected peroxycarbenium ions (42), generated from acetals (41) on treatment with SnCL, have been developed as the optimal reagents to effect addition to alkenes, which gives rise to a variety of 1,2-dioxolanes (43) in 28-92% yields. This novel method allowed the synthesis of plakinic acid analogues in three steps from the corresponding ketone and alkene.53... 

Monoperoxyacetal 262, when treated with TiCl4, produced an intermediate, presumably a peroxycarbenium ion, that was capable of undergoing a endo-endo-intramolecular cyclization with the alkene moiety to give, in low yield, a 2.4 1 mixture of diastereomers of the perhydro-dioxocin 263 (Scheme 51) C1995JOC784, 2000JOC8407>. 

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