4a. n. 2 bn 3 in carbohydrate chemistry (inter alia) where the advantages of this exceptionally good leaving group have provided the basis of (i) a convenient synthesis of deoxyhalogeno sugar^,^(ii) highly stereoselective syntheses of 8-or a-glycosides and disacharide~+~ and (iii) the preparation of benzyl ether derivatives of appropriately protected carbohydrates. 6p7
