Deuterium-isotope study on the reductive ring opening of benzylidene acetals†
Abstract
Specific deuterated reference compounds were prepared to probe the stereoselectivity of the reductive ring opening of carbohydrate-based benzylidene-type acetals. AlD3 revealed a retentive stereoselectivity probably through the rare SNi (internal nucleophilic substitution) mechanism. An SN1-like mechanism occurs in the acid-promoted regioselective BD3·THF- or Et3SiD-reductive ring opening.