Chemistry of organosilicon compounds. 93. New photochemical reactions of vinyldisilanes through silaethene or silacyclopropane intermediates

Photolysis of organopolysilanes. Generation and reactions of silicon-carbon double-bonded intermediates

“…However, with benzophenone, unexpected adducts, (E)-and (Z)-1-benzhydroxydimethy1si1y1-1-pheny1-2-trimethy1si1y1et hene (47) (22% yie1d) in a ratio of 4/1 were obtained, together with 22% yie1d of an expected o1efin (46). With viny1 ketone, ~ produced two types of products, (E)-and (Z)-3-methy1-4-pheny1-5-trimethy1si1y1-1,3-pentadiene (~ and~) and 2,6,6-trimethy1-5-trimethy1si1y1methy1-5-pheny1-1-oxa-6-s i1a-cyc1ohexene-2 (49) in 8 and 18% yie1d, respective1y (24 Photochemical behavior of ß-styrylpentamethyldisilane (50a) is different from that of the above-mentioned a-isomer (25,26). Irradiation of 50a with methanol in benzene afforded an equilibrium mixture of cis and trans isomers in a ratio of 1/1.…”

Synthesis and Photochemistry of 1,2-Digermacyclohexa-3,5-dienes and Related Compounds

“…This reminds us of the photochemistry of vinyldisilane and -digermane. The vinyldisilane 12 is transformed to either the corresponding silacyclopropane 14 or silene 15 via 1,2- or 1,3-Si migration, respectively (eq 6), − but in contrast, the vinyldigermane 13 is converted to vinylgermane 16 with extrusion of the corresponding germylene via 1,2-Ge migration or possibly a germacyclopropane or its equivalent 17 (eq 7) . On the other hand, one of the silicon analogues of 1,3-cyclohexadiene, namely a 1,2-disilacyclohexa-3,5-diene, has been reported to undergo quantitative photochemical isomerization to afford 2,6-disilabicyclo[3.1.0]hex-3-ene and 5,6-disilabicyclo[2.1.1]hex-2-ene, possibly by way of a conjugated disilatriene intermediate …”

Evidence for the generation and trapping of a silabenzene

“…The generation of silenes at lower temperatures has been accomplished photolytically (6,33,(78)(79)(80)(81)(82)(83)(86)(87)(88)(89)(90)(91)(92)(93)(94)(95)(96)(97)(98) Koob and co-workers (80) recently reported the vacuum photolysis of 1,1-dimethyl-l-silacyclobutane ^ (R = Me) (Scheme 5)-Evidence for 2-methyl-2-silapropene was also reported as formation of the methanol adduct, methyltrimethylsilylether ^ (R = Me). In the absence of traps, only a very low yield of 1,3-disilacyclobutane, the dimer normally found in thermal reactions, is observed.…”

“…This work is discussed in detail elsewhere The photochemical behavior of phenyl substituted disilanes has received considerable attention (83,(90)(91)(92)(93)(94)(95)(96)(97)(98)(99) process.…”