Science of Synthesis

von Angerer, S.; Warriner, S. L., Science of Synthesis, (2007) 29, 334.

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]

‌Meeeee 88‌ Meeeeeeee ee Meeeeee ee Meeeeeeeee ee eee Meeeeeeeee Meeeeeeeeeee[‌888‌,‌888‌]

‌Meeeeeeeeee 88‌

Mee eeeeeeee ee eeeeeeee eeeeeeeee eeee eeeeeeee ee eeee eeeeeee eeee ee ‌88‌ eee ‌88‌ eee ee eeeeeeeee eeeeeeee eeeee eeeeeeee eeeeeeeeee, eeee eeeeeeee eeeeeee ee eee eeeeeeeeee eeeee. Meeeeeeee eeee eeeeeeee-eeeeeeeeeee eeeeee eeeee ee eeee eeeeeeeeeee eeee eeeeeeee eeeeeee eeeee eee eeeeeee eee eeee eeeee ee eeeeee eeeeeeeee eeeeeeee (‌Meeeee 88‌),[‌888‌] eeeeeee eeeee eeeeeeeee eeee ee ee eeeeee eee eeee eeeeee ee eeee eeeee ee eee eeeeeeee ee eee eeee.[‌888‌]

‌Meeeee 88‌ Meeeeeeee ee Meeeeeee Meeeeeee Meeeeee eeeee Meeeeeee Meeeeeeeee[‌888‌]

M eeeeeee eeeeeeeee eee eee eeeeeeeeeee ee eeeeeee ee eee eeeeeeee ee α,β-eeeeeeeeeee eeeeeeeee ee eeeeeee eeee eeeeeeee eeeeeeeee ee eeeeeee eeeeeeeeeeeeeeeee, eeeeeeeeeeee, ee eee eeeeeeee ee eeeeeee.[‌888‌,‌888‌] Mee eeeeeeeeeeeeeee eeee eeeeee eee M=M eeee eee eeeeeeeee eee eeeeeeeeee eeeeeeeeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meeeeeee ee α,β-Meeeeeeeeee Meeeeeee Meeeeeeee eeee Meeeeeee Meeeeeeee[‌888‌]

Meeeee eeeeeeeeeee eee eeeeeeeee eeeeeeeeee eee eee eeeeeeeeee eeeeeeee. Mee eeee eeeeeeee eeeee ee ee eeeeeeeee eeeeeeeeeeeeeeeeeeeeee ee eeeeee eeeeeee, eee eeeeeeeeeee eeee eeee eeeeeeeee eeee e eeeee ee eeeee eeeeeee, e.e. eee eeeeeeeee ee eeeeee ‌88‌ (‌Meeeee 88‌).[‌888‌–‌888‌] Meeee eeeeeeeeeeeeeeeeeeeeeeeeee eeee eeee eeee eeee. Me eeeee eeeeeeeeee eee eee eeeeeee, eeeeeeeeeee eee ee eeeeeeeee eeeee e eeeeeeeeeee ee eeeeeeeeeee eee eeeeee(M) eeeee eeeee eeeeeeeeeee eeeeeee eeeeeeeeee.[‌888‌] Meeeee eeeeee eeeeeeeeee eeeeee eee eeee eeeeeeeeeeee eeeeeeeeeeee ee eeeeeee eeeeeeeee eeeeeeee ee e eeeee ee Meeeeee eeeeeeeee, eeee eeeeeeeee eeeeeeeeeeeeeeeeeeee.[‌888‌–‌888‌]

‌Meeeee 88‌ Meeeeeeeee ee Meeeee Meeeeeeeeee[‌888‌–‌888‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeeeee ‌88‌; Meeeeee Meeeeeeee:[‌888‌,‌888‌]

MMMMMMM: Meeeeeee eeeeeee ee eeeeeeeee eee eeeeeeeeee ee eee eeee, eeee, eee eeeeeeeeeee eeeeee eee ee e eeeeeeee eeeee eeeeeeeeee.

Meeeee M:[‌888‌] Mee eeeeeee (8.88 eee) eee eee eeeeee ‌88‌ (8.88 eee) ee MMM eee eee eeeeeee eeeeeee[‌888‌] eeee eeeee. Meeee eeeeeeeee ee eeeeeeee, eee eeeeeeee (8.88 eee) eee eeeee eeeeeeee eeee eeeeeeee eeeeeeee. Meeee eee eeeeeeee, eee eeeeeee eee eeee ee ee eee 8 e ee eeeee eee eeeeeeeee ee eee eeeeee. Mee eeeee eeeee eee eeeeeeeee eee eee eeeee eeeee eeeeeeeee eeee Me8M (8 × 88 eM). Mee eeeeeeee eeeeeeee eeee eeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eeeee ee eee eeeee eeeee. Mee eeeeeeee eeeeee eee eeeeeeeee ee eee eeeeeeee ee eeeee M8MM8 eeeeeee e 88-ee Meeeeee eeeeee; eeeee: 88–88%.

Meeeee M:[‌888‌] Mee eeeeeeee eeeeeeee (8.88 eee) eee eeeee eeee eeeee MeMM ee MeMM (8.88 eee) eee eee eeeeee ‌88‌ (8.88 eee) ee MMM eee eeeeeeee ee eeeeeee eeeeeee;[‌888‌] eee eeeeeee eee eeeeeee ee 88°M eee 88 ee 88 e. Meee eeeeeee, Me8M (8.88 eee) ee eeeeeee (88 eM) (MMMMMMM: eeeeeeeeee) eee eeeee eeee eeeeeeee. Mee eeeeeee eee eeee eeeeeeeee eeee eee. MeMMM8 eeee (8 × 88 eM) eee eee eeeeeee eeeee eee eeeee (M8MM8). Meeee eeeeeee ee eee eeeeeee, eee eeeeeee eee eeeeeeeee eeeee eeeeeee eeeeeeee eeeee e 88-ee Meeeeee eeeeee; eeeee: 88–88%.

Meeeeee ‌88‌ eee ‌88‌; Meeeeee Meeeeeeee:[‌888‌]

MMMMMMM: Meeeeeee eeeeeee ee eeeeeeeee eee eeeeeeeeee ee eee eeee, eeee, eee eeeeeeeeeee eeeeee eee ee e eeeeeeee eeeee eeeeeeeeee.

M eeee ee eee eeeeeeee (8 e) ee MeMM (88–88 eM) eee eeeee eeee eee eeeeeeeeee eeeeee ee Me8MM8 (8.8 e eee eeeeeeeeeeeeeeeeee eee 88.8 e eee eeeeeeeeeeeeeeeeee). Meee 88 eee eee eeee eee eeeee eeeeeeee ee 8 M ee MeMM (8.8–8.8 eee eee eee Me8MM8), eeee eeeeeeee eee eee eeeeeee. Meeee eee eeeeeeee, eee eeeeeee eee eeeeeeee eee 88 eee. Meeee eeeeeee ee ee, eee eeeeeee eee eeeeeeeee eeee Me8M. Meeee eeeeeeeeeee ee eee Me8M, eee eeeeeee eee eeeeeee eeee e eeee ee MM8MM•MMe ee eee MeMM eee eeee eeeeeeeee eeee Me8M. Mee eeeeeee eeeee eee eeeeeeeee eeeeeee eeeee eeee eee MeMM. Mee eeeeeeee eeeeeee eeeeee eeee eeeeeeeee eeee Me8M eee eee eeeeeeee eeeeeee eeeee eeee eeeee (M8MM8). Meeee eeeeeeeeeee ee eee eeeeeee, eee eeeeeee eee eeeeeeee ee eeeeeeeeeeee eeeee eeeeeee eeeeeeee; eeeee: 88–88%.

8-Meeeee-8-(eeee-8-eeeeeee)eeeeeeeeeeeeeee (‌88‌):[‌888‌]

M 8.8 M eeee ee MMMMM ee eeeeeee (8.8 eM, 8.8 eeee) eee eeeee eeeeeeee ee e eeee ee 8-eeeeeeeeeeeeeeeeeeeee-8-ee (8.88 e, 8.88 eeee) ee MMM (8.8 eM) ee −88°M. Mee eeee eee eeeeeee ee −88°M eee 88 eee, eee eeee 8-eeeeeeeee-8-eee (8.88 e, 8.8 eeee) eee eeeee eeeeeeee eee eeeeeee. Mee eeeeeeee eee eeeeeee ee eeee ee ee eee eeeeeee eee e eeeeeee 8 e. Mee eeeeeee eee eeeeeee eeee Me8M (88 eM), eee eeee eeeeeeee ee eee eeeeeeee ee M8M (8 eM). Mee eeeeeee eeeee eee eeeeeeeee, eeeeee eeee 8 M ee MMe (8 × 88 eM) eee eee. MeMe eeee (88 eM), eeeee (MeMM8), eee eee eeeeeeeee eeee eeeeeee eeeee eeeeeee eeeeeeee ee eeeee e eeeeee eee. Meeeeeeeeeee eee ee eeeeeeeeeeeeee (eeeeee eee, eeeeeeeee eeeee/MeMMe 88:8); eeeee: 8.88 e (88%).

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 8/8, 888.
• 8.Meeeee-Meee, (8888) 8/8, 888.
• 8.Meeeee-Meee, (8888) M 88e8, 888.
• 8.Meeeee-Meee, (8888) M 88e8, 888.