Molybdenum(V)-mediated switching of the C(sp2)-Se bond of phenylselenyl-functionalized arenes or heterocycles under mild conditions.

Molybdenum(V)-mediated cleavage of C(sp2)-Se bond and C(sp2)-H bond as well as intramolecular oxidative C(sp2)-Se coupling reaction of phenylselenyl-functionalized arenes or heterocycles has been developed. Three kinds of benzoselenophene frameworks were constructed through this reaction with yields up to 94%. This new C(sp2)-Se bond-switching methodology may provide a new strategy for interesting applications of phenylselenyl-substituted aromatic compounds in the synthesis of selenium-containing heterocycles and natural products.

Silver-catalysed three-component reactions of alkynyl aryl ketones, element selenium, and boronic acids leading to 3-organoselenylchromones.

An Ag-catalysed three-component reaction of alkynyl aryl ketones bearing an ortho-methoxy group, element selenium, and arylboronic acid, providing a facile route to selenofunctionalized chromone products has been developed. This protocol features high efficiency and high regioselectivity, and the use of selenium powder as the selenium source. Mechanistic experiments indicated that the combined oxidative effect of (bis(trifluoroacetoxy)iodo)benzene and oxygen in the air pushes the catalytic redox cycle of the Ag catalyst and the phenylselenium trifluoroacetate formed in situ is the key intermediate of the PIFA-mediated 6-endo-electrophilic cyclization and selenofunctionalization reaction of alkynyl aryl ketones.