51110-88-4Relevant academic research and scientific papers
Sulfuranes with Oximate Axial Ligands
Hornbuckle, S. F.,Livant, P.,Webb, T. R.
, p. 4153 - 4159 (2007/10/02)
New sulfuranes having one or two axial oximate (R2C=NO) ligands were synthesized.An improved sulfurane-forming step, involving a rapidly stirred suspension of NaHCO3, is described.The failure of sulfide oximes in which sulfur bears one or two tertiary carbons to form sulfuranes is explained by a C-S bond cleavage leading to tertiary carbocations.This represents a hitherto unanticipated limitation to the standard method of sulfurane synthesis.The X-ray crystal structure of one of the new sulfuranes, namely 2,2'-spirobi(4-phenyl-3H-1,2,5-oxathiazoline), is reported (R = 0.0368).An unusual feature was the quite compressed equatorial (C-S-C) angle, 102.6(1) deg.The S-O bond length, 1.846(2) Angstroem, was similar to S-O bond lenghths of sulfuranes having two axial carboxylate ligands.Since the oximate ligand has not been used previously in a 10-S-4 species, an assessment of its apicophilicity relative to other more common axial ligands was made by considering X-ray structural data, IR data, and ab initio calculations.These suggest that the R2C=NO ligand is as apicophilic as the hexafluorocumyloxy (ArC(CF3)2O) ligand.
Synthesis, Chemical Properties, and Structure of a Sterically Hindered Ketone, 2,2,5,5-Tetramethyl-4,4-diphenyl-3-thiolanone
Nakayama, Juzo,Hirashima, Atsushi,Yokomori, Yoshinobu
, p. 3593 - 3599 (2007/10/02)
A sterically hindered ketone 2,2,5,5-tetramethyl-4,4-diphenyl-3-thiolanone (1), was synthesized in two steps starting from 2,2,4,4-tetramethyl-1,5-diphenyl-1,5-dione.The carbonyl group of 1 is unreactive toward a series of nucleophiles which are bulkier than hydride or its equivalents.The observed unreactivity is ascribed to the steric hindrance enhanced by the two methyl groups on C-5 ("buttressing" effect).The results of an X-ray single crystal structure analysis of 1 is also described.
