Formaldehyde → 2-(2,4-Dichlorophenyl)-2-(phenylsulfonyl)ethyl acetate

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Reaction Steps

The crude sulfone (2) (1 eq) in THF was added dropwise via addition funnel to a freshly prepared solution of diisopropylamine (1.3 eq), n-BuLi 2.5 M in hexanes (1.1 eq) and THF under N2 at −78° C. with stirring. After 30 min., the paraformaldehyde was added (2.1 eq). The reaction was stirred for an additional 30 min. at which time the reaction was allowed to warm to room temperature over 4.5 h. The reaction was then quenched with sat. aq. NH4Cl. The aqueous layer was extracted with EtOAc, dried (Na2SO4), filtered and concentrated under reduced pressure to yield the crude sulfonyl hydrin which was used without further purification. The crude sulfonyl hydrin was dissolved in CH2Cl2 (excess) and pyridine (1.2 eq) followed by the addition of Ac2O (1.1 eq). After stirring at room temperature for 14.5 h, the reaction was quenched with sat. aq. NH4Cl. The layers were separated, and the aqueous layer was extracted with Et2O. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the 2-(2,4-dichlorophenyl)-2-(phenylsulfonyl)ethyl acetate (3) (94% yield) in high purity.

Provenance & Evidence