Brigl anhydride, synthesis

As has already been mentioned, even 3,4,6-tri-0-acetyl-l,2-anhy-dro-a-D-glucopyranose (Brigl s anhydride, 5) may be exploited for the synthesis of levoglucosan (see Sect. 11,1). 

A 31% yield of octar-0-methyl-a,a-trehalose was obtained by reversion of 2,3,4,6-tetrarO-methyl-D-glucose with concentrated hydrochloric acid. Haq and Whelan - obtained a,a-trehalose as a byproduct in the synthesis of 2-0-a-D-glucopyranosyl-n-glucose from Brigl s anhydride. 

The first reported synthesis of peracetylated 1-thio-a-D-glucopyranose started from the Brigl s anhydride [9] but traditionally, 1,2-cw-thioglycoses have been generated from the 1,2-tranj-glycosyl halides by reaction of alkyl or benzyl xanthates in acetone [13], potassium thioacetate in hexamethylphosphoramide (HMPA) [14], or the tetrabutylammonium salt of thioacetic acid in toluene [15] (Scheme 1). A recent alternative is the peroxide-induced addition of thioacetic acid to hydroxy-glucal derivatives [16]. 

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