5927-28-6Relevant articles and documents
Solution-Phase Far-UV Photochemistry of Unsaturated Organosilanes: Dehydrosilylation, Dyotropic Rearrangement, and Protodesilylation
Steinmetz, Mark G.,Langston, Mark A.,Mayes, Richard T.,Udayakumar, B. S.
, p. 5051 - 5063 (1986)
Photolysis of 1,1,3,3-tetramethyl-1,3-disilacyclopentene (1) at 214 nm in methanol, 2,2,2-trifluoroethanol, or tert-butyl alcohol gave 5-alkoxy-3,3,5-trimethyl-3,5-disila-1-hexenes 4a (RO = methoxy, 25percent), 4b (RO -2,2,2-trifluoroethoxy, 30percent), or 4c (RO = tert-butoxy, 24percent), 4-11percent yields of 1,1,3,3-tetramethyl-2-methylene-1,3-disilacyclobutane (2), 5-7percent yields of 2,4,4-trimethyl-2,4-disila-5-hexyne (3), and 1 recovered in 50percent, 29percent, and 24percent yields, respectively.In tert-butyl alcohol 10percent of 2-(tert-butoxymethyl))-1,1,3,3-tetramethyl-1,3-disilacyclobutane (6) and 5percent 4-tert-butoxy-1,1,3,3-tetramethyl-1,3-disilacyclopentane (5) were also obtained.Both direct or xylene-sensitized photolyses of 1 in methanol-O-d1 led to >89percent C1 monodeuteriation of 4a with 94percent (direct) or 87percent (sensitized) of the label trans to the vinylsilicon, while opposite stereospecifity, i.e. cis deuteriation of the vinyl group , was observed on reflux in acidic methanol-O-d1.Stereospecific (85percent) trans deuteriation of the vinyl group of 4c-d1 was observed on direct photolysis in tert-butyl alcohol-O-d1, and 5 was labeled at C4 and 6 at the carbinyl carbon attached to C2.The deuterium-labeling results imply two carbocation precursors to 5 and 6.The occurence of photoprotonation in both the excited singlet and triplet states of a constrained cycloalkene such as 1 is highly exceptional and its interpretable in terms of potential reactivity of a 90 deg twisted, ionic ground-state intermediate or intramolecular charge-transfer 1,3?,?* states.
Radical Rearrangements in the Pyrolysis of Allyldisilanes
Barton, Thomas J.,Jacobi, Stephanie A.
, p. 7979 - 7981 (2007/10/02)
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