“…(c) α(1,2,3)-β(4)-1,2-O-Isopropylidene-O3-sulfonates (eq ) ,− ,− and their α(1,2,3,4)-1,2-O-isopropylidene-O3-sulfonate counterparts (eq 17) ,− both readily engage in S N 2 displacements with charged nucleophiles, but elimination is sometimes problematical for the latter type of substrate, particularly when the nucleophile has significant basicity. This is due to H(4) being anti with respect to the C(3)–OSO 2 R group and the latter acidifying these H atoms by electron withdrawal.
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