A Convenient Synthesis of Protected α-Hydroxyacetaldehydes

Conversion of Epoxides to 1,3-Dioxolanes Catalyzed by Tin(II) Chloride

“…8, 128.2, 127.7, 125.9, 109.4, 77.8, 71.5, 26.5, and 25.9. 2,2-Dimethyl-4-[(phenylmethoxy)methyl]-1,3-dioxolane (4e). 23 Anhydrous SnCl2 (9.5 mg, 0.05 mmol), acetone (25 mL), and epoxide 3e (0.76 mL, 5 mmol) yielded 4e (0.886 g, 80%) after MPLC (12:1 hexanes/ethyl acetate). 1 H NMR (CDCl3, 300 MHz): δ 7.32 (m, 5H), 4.57 (AB, J ) 12.3, 2H), 4.29 [dddd (app tt), J ) 6.2, 5.6, 1H], 4.05 (dd, J ) 8.2, 6.2), 3.73 (dd, J ) 8.2, 6.5, 1H), 3.55 (dd, J ) 10.0, 5.6, 1H), 3.46 (dd, J ) 10, 5.6, 1H), 1.42 (s, 3H), and 1.36 (s, 3H).…”

Ring-Expanded Nucleoside Analogues. 1,3-Dioxan-5-yl Pyrimidines

“…2-Substituted-1,3-dioxanes (also 1,3-dithianes, 1,3-oxathianes) are conveniently prepared by cycloacetalization of aldehydes with 1,3-diols (or 1,3-dithiols, 3-mercapto alcohols). Benzoyloxyacetaldehyde, a protected α-hydroxyaldehyde, reacted well with the 1,3-dihydroxy-2-propyl-substituted pyrimidines ( 9a − c ) to afford cis/trans mixtures of the 1,3-dioxanes 11a − c . Under the conditions employed (no solvent, TsOH catalyst, 80 °C, 2−3 mmHg), the desired cis stereoisomers were the major products, constituting 70−86% of the crude cyclization mixtures.…”

An efficient approach to enantiomeric isoxazolidinyl analogues of tiazofurin based on nitrone cycloadditions

“…(Scheme 1). Nitrone 7 was prepared in situ from the condensation of aldehyde 16, obtained from (±)-solketal, 25 with an equimolar amount of hydroxylamine 17 obtained from D D-ribose.…”