Photochemistry of 1-aryl-4-(pentamethyldisilanyl)buta-1,3-diynes: photoreaction with acetone and dimethyl fumarate

Abstract

Irradiation of 1-aryl-4-(pentamethyldisilanyl)buta-1,3-diynes (1–3) with acetone yields site specific and regioselective 1 : 1 adducts (4–8)via silacyclopropene intermediates. Photoreaction of 1-aryl-4-(pentamethyldisilanyl)buta-1,3-diynes with dimethyl fumarate gives two-atom insertion products (9 and 13)via silacyclopropene and/or [2 + 2] photocycloaddition products (10–12 and 14). The silacyclopropene intermediates are formed from singlet excited states in compounds 1 and 2, but from the triplet excited state in compound 3.