The Pummerer-like reaction of 2,5-bis(trimethylsilyl)thiopheneS-oxide with trifluoroacetic anhydride: intermediary formation of sulfurane [10-S-4(C2O2)] (?4-sulfane)
X-Ray Crystallographic Analysis of 2,5-Bis(diphenylmethylsilyl)thiophene Monooxide and the Diels-Alder Reaction of Thiophene Monooxide with Dienophiles
X-Ray crystallographic analysis of 2,5-bis(diphenylmethylsilyl)thiophene monooxide revealed that the thiophene ring is not a planar structure and that the S-O bond is tilted ca. 14 degrees out of the ring plane. The Diels-Alder reaction of 2,5-bis(trimethylsilyl)thiophene with dienophiles gave the adducts in high yields. The stereochemical courses for the reactions are exclusively endo-orientation and syn-direction with respect to the S-O bond. This stereochemistry agrees with the results obtained from RHF and MP2MO calculations using the 6-31G(*) basis set.
Simple Procedure for the Synthesis of 2,5-Bis(silylated) Thiophene S-Oxides with m-Chloroperbenzoic Acid in the Presence of BF3(Et2O)
Oxidation of 2,5-bis(silyl)thiophenes (1) with m-chloroperbenzoic acid (m-CPBA) in the presence of BF3(Et(2)O) gave the corresponding S-oxides (2) in moderate yields, while, without BF3(Et(2)O), the oxidation gave solely the corresponding thiophene S-dioxides (3) and no S-oxide was obtained at all. This procedure was successfully applied to the synthesis of other 2,5-bis-substituted thiophene monooxides.
Photochemistry of thiophene-<i>S</i>
-oxide derivatives
作者:Melanie J. Heying、Mrinmoy Nag、William S. Jenks
DOI:10.1002/poc.1384
日期:2008.11
Photolysis of substituted thiophene-S-oxides in solution results in the formation of either the corresponding thiophene or furan, in addition to uncharacterized materials. No good rationalization is available for the choice of which pathway may predominate, but it is demonstrated that the photolysis of 2,5-bistrimethylsilylthiopene- S-oxide produces O(3P) in the same manner as the well-established