4-(1,3-DIOXAN-2-YL)BENZALDEHYDE synthesis

Yield:81172-92-1 83%

Reaction Conditions:

with sodium hydride;zinc(II) chloride in tetrahydrofuran;mineral oil at 40; for 3 h;Inert atmosphere;Sealed tube;

Steps:

Reduction of Nitriles 1 and 3 to Aldehydes 2 and 4; General Procedure

General procedure: To a mixture of NaH (60% dispersion in mineral oil; 60.0 mg, 1.50 mmol) and ZnCl2 (102 mg, 0.750 mmol) in a 25-mL sealed tube was added a solution of nitrile 1 or 3 (0.500 mmol) in THF (2.5 mL). The mixture was sealed and stirred at 40 °C. The reaction was quenchedby following one of the two protocols. Workup protocol 1: Upon full consumption of the nitrile (TLC or GC monitoring), silica gel (2.0 g) was added to the mixture and it was diluted with hexane (10 mL) at 0 °C. The resulting mixture was stirred for 1 h at 24 °C. The mixture was then filtered through layers of cottonand sand and washed with EtOAc. The volatile materials were removedin vacuo from the resulting filtrate. The crude residue was purified by flash column chromatography to give the corresponding aldehyde 2 or 4. Workup protocol 2: Upon full consumption of amide (TLC or GC monitoring), the reaction was quenched with pH 10 ammonium buffer at 0°C and the organic materials were extracted with CH2Cl2 (3 × 20 mL). The combined organic extracts were dried (MgSO4). The volatile materials were removed in vacuo and the resulting crude residue was purified by flash column chromatography to give the corresponding aldehyde 2 or 4.

References:

Chiba, Shunsuke;Ong, Derek Yiren [Synthesis,2020,vol. 52,# 9,p. 1369 - 1378]