PP-24 Unusual Product from the Reaction of 1,2:3,4:5,6 -Tri-o-Isopropylidene-D- Gluconolactone with Benzothiazol-2-Ylmethylsulfone under Julia Conditions Indrapal Singh Aidhen*, Manjunath. B. N. Department of Chemistry, Indian Institute of Technology Madras Chennai 600036 isingh@iitm.ac.in Olefination of sugar lactones has enabled access to methylene exo-glycals 1 as valuable intermediates for the synthesis of C-glycosides 2 and C-disaccharides 3 . The olefination procedures are usually based on the use of Tebbe reagent 4 or dimethyltitanocene, 5 Ramberg-Backlund rearrangement in glycosyl sulfones 6 or Bamford-Stevens reaction of anhydroaldose tosylhydrazone. 7 Very recently there appeared one isolated report using Julia olefination strategy for the same objective 8 . In fact this constitutes the first successful reaction of methyl-sulfone 3 with sugar-lactone derivatives towards the objective of olefination. During our attempts for olefination of the tri-isopropylidene lactone 1, we were surprised to find no formation of the expected exo-methylene product 2, but led to exclusive formation of an unusual product 4. The poster would present these research findings and also the details of unambiguous confirmation of the proposed structure to the unusual product obtained. S O O S N O O O O 1: X = O 2: X = CH 2 O O X O O O O O N S O 3 4 References 1 Taillefumier, C.; Chapleur, Y. Chem .Rev. 2004, 104, 263. 2 (a) Brockhaus, M.Lehmann, J. Carbohydr.Res. 1977, 53, 21. (b) Lehmann, J.; Schwesinger, B., Carbohydr.Res. 1982, 107, 43. 3 (a) Nicotra, F.; Panza, L.; Russo, G. Tetrahedron Lett. 1991, 32, 4035. (b) Gervay, J.; Flaherty, T.M.; Holmes, D. Tetrahedron 1997, 53, 16355. (c) Faivre-Buet, V.; Eynard, I.; Nga, H.N.; Descotes, G.; Grouiller, A. J. Carbohydr. Chem. 1993, 12, 349. 4 Waldscheck, B.; Streiff, M.; Notz, W.; Kinzy, W.; Schmidt, R. R. Angew. Chem. .Int. Ed. 2001, 40, 4007 . 5 Johnson, C. R.; Johns, B. A. Synlett 1997, 1406. 6 Griffin, F. K.; Murphy, P. V.; Paterson, D.E.; Taylor, R. J. K. Tetrahedron Lett. 1998, 39, 8179.