Activations 1 benzenesulfinyl piperidine

To a solution of thioglycoside (1.0 equiv), 1-benzenesulfinyl piperidine (1.0 equiv), TTBP (2.0 equiv), and freshly activated 3 A powdered molecular sieves in dichloromethane (25.0 ml mmol-1) was added trifluoromethanesulfonic anhydride (1.1 equiv) at —60 °C under an argon atmosphere. The reaction mixture was stirred for 5 min, after that a solution of the glycosyl acceptor (1.5 equiv) in dichloromethane (4.0 ml mmol-1) was added. The reaction mixture was stirred at — 60 °C for 2 min, after that it was slowly warmed to room temperature and quenched by the addition of saturated aqueous NaHC03. The organic layer was washed with brine, dried (MgS04), filtered and the filtrate was concentrated to dryness. Purification of the crude product by column chromatography over silica gel afforded the product. 

Crich D, Banerjee A, Li W, Yao Q. Improved synthesis of 1-benzenesulfinyl piperidine and analogs for the activation of thioglycosides in conjunction with trifluoromethanesulfonic anhydride. J Carbohydr Chem 2005 24 415-424. 

To obtain more support for the remote participation of 3-0-acyl and 6-0-acetyl groups in mannosyl donors, Kim and co-workers carried out experiments to trap anomeric oxocarbenium ion intermediates by the intramolecular nucleophilic attack of the trichloroacetimidoyl group at the 0-3 position of mannosyl donors the activation of 72 with 1-benzenesulfinyl piperidine (BSP) and Tf20 afforded... 

This limitation of activation has been overcome by the combination of 1-benzenesulfinyl piperidine (BSP) and Tf20. ... 

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