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29.6.1.2.3.4 Variation 4: From Alcohols and Alkylating Agents

DOI: 10.1055/sos-SD-029-00368

von Angerer, S.; Warriner, S. L.Science of Synthesis, (200729334.

An alternative route to acetals 34 involves alkylation of the hemiacetals. This procedure only works well with aldehydes that readily form hemiacetals, e.g. aliphatic aldehydes, benzaldehyde, and aromatic aldehydes with electron-withdrawing substituents, along with cyclic hemiacetals. Appropriate alkylating agents are the adducts 33 formed by dimethyl or diethyl sulfate with dimethylformamide (Scheme 42).[‌291‌,‌292‌] Aliphatic α,β-unsaturated aldehydes also add the alcohol across the C=C bond, giving the corresponding 3-alkoxy acetals in good yield.[‌292‌] Among the ketones investigated, only cyclohexanone gives reasonable yields of the dimethyl (74%) and diethyl (62%) acetals.[‌292‌]

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Meeeeee 88 eee 88; Meeeeee Meeeeeeee:[‌888‌]

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References