Compound 2a

3-[1,3-Dihydro-1,3-bis(1-methylethyl)-4,5-dimethyl-2H-imidazol-2-ylidene)]-4,8-bis-[2,6-bis(1-methylethyl)phenyl]-5-methyl-7-methylene-1,2-dioxa-4,8-diaza-3-sila-spiro[2.5]oct-5-ene

From: From silicon(II)-based dioxygen activation to adducts of elusive dioxasiliranes and sila-ureas stable at room temperature