Methanesulfonylation selective

Selective esterification, particularly p-toluenesulfonylation and methanesulfonylation, of one, or two, of several hydroxyl groups in carbohydrate molecules is an important reaction for constitutional and configurational alterations. 

Pyrolysis or photolysis of methanesulfonyl azide in 2-methyl butane (RH) produces formal C H insertion adducts attributed to reactions of the thermally generated nitrene. The selectivity of this nitrene for 3°/2°/l° C—H bonds was 6/2.3/1.0 Sulfonyinitrenes, like acylnitrenes, insert into the OH bonds of alcohols. 

The importance of sugar sulfonates as synthetic intermediates has been widely recognized.77,78 Selective methanesulfonylation and p-toluenesulfonylation of maltose and its derivatives has been studied. Umezawa and coworkers used sequential p-toluenesulfonylation and acetylation to obtain crystalline l,2,3,2, 3, 4 -hexa-0-acetyl-6,6 -di-0-p-tolylsulfonyl-/3-maltose in 45% yield.79 Dimolar methanesulfonylation of methyl /3-maltoside followed by acetylation afforded crystalline methyl 2,3,2, 3, 4 -penta-0-acetyl-6,6 -di-0-(methylsulfonyl)-/3-maltoside. The mother liquor also yielded a small proportion of a... 

Selective sulfonylation of 1 A/i -tri-O-tritylsucrose (activated by Bu2SnO) with methanesulfonyl chloride in benzene afforded the 3-mesylated derivative, whereas the same process performed in toluene surprisingly provided the 4-mesylate in 50% yield. If triflic anhydride is used as the sulfonating reagent, the 4-triflate was obtained in 40% yield (Scheme 12).153... 

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