Silicon Compounds with Strong Intramolecular Steric Interactions. LVII . Oxidation and Cycloaddition Reactions of an Unsymmetrically Substituted Disilene

Reaction of the unsymmetrically substituted disilene R 2 Si=SiR′ 2 ( 4 ; R = 2,4,6‐Me 3 C 6 H 2 , R′ = 2,4,6‐ i Pr 3 C 6 H 2 ) with m ‐chloroperbenzoic acid ( m CPBA) or oxygen furnished the correspondingly substituted 1,2,3‐oxadisilirane 5 or 1,3,2,4‐dioxadisiletane 6 , respectively. The [2 + 2] and [2 + 4] Cycloaddition reactions of 4 with benzophenone and 3,5‐di‐ tert ‐butyl‐1,2‐benzoquinone, respectively, proceeded with a high degree of regioselectivity to yield the 1,2,3‐oxadisiletane 9 and the 2,3‐dihydro‐1,4,2,3‐benzodioxadisiline 7 . The latter product was isolated together with a small amount of an isomeric compound 8 in which the substituents at the silicon atoms are reversed. The molecular structures of the products 5, 6 , and 7 were determined by X‐ray crystallography.