A New Synthesis of trans-2,3-Diaryloxiranes and 2-(1H-Benzo[d][1,2,3]-
triazol-1-yl)-1-arylethanols via the Reactions of 1-Benzyl-3-methylbenzo-
triazolium Ylide with Aryl Aldehydes

Abstract

1-Benzyl-3-methylbenzotriazolium ylide was formed by the reaction of 1-benzyl-3-methylbenzotriazolium iodide with t-BuOK. Subsequently it reacted with various aryl aldehydes to give the corresponding trans-2,3-diaryloxiranes and 2-(1H-benzo-[d][1,2,3]triazol-1-yl)-1-arylethanols in moderate to high yields.

Key words

ammonium ylide - 2,3-diaryloxirane - benzotriazole - Darzens reaction - 2-(1H-benzo[d][1,2,3]triazol-1-yl)-1-arylethanol

References and Notes

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Process A: BMeBt iodide (1; 3 mmol), benzaldehyde (2a; 3 mmol), t-BuOK (3 mmol) and solvent (10 mL) were mixed together and stirred at r.t. After the purple color of the solution had faded, H₂O (25 mL) was added and the products were extracted with EtOAc (3 × 25 mL). The combined organic phases were washed with brine (2 × 25 mL) and H₂O (25 mL), and then were dried over anhyd Na₂SO₄, filtered and concentrated in vacuo. The residue was separated by column chromatography.

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Process B: A solution of BMeBt iodide (1; 3 mmol) and aryl aldehyde 2 (6 mmol) in DMSO (5 mL) was added dropwise to the stirred solution of t-BuOK (6 mmol) in t-BuOH (5 mL) at r.t. After the purple color of the solution had faded, H₂O (25 mL) was added and the products were extracted with EtOAc (3 × 25 mL). The combined organic phases were washed with brine (2 × 25 mL) and H₂O (25 mL), and then were dried over anhyd Na₂SO₄, filtered and concentrated in vacuo. The residue was separated by column chromatog-raphy to afford the corresponding trans-2,3-diaryloxiranes 3 and 2-(1H-benzo[d][1,2,3]triazol-1-yl)-1-arylethanol 4.