Methyl phenyl sulfone → 3-((Phenylsulfonyl)methylene)oxetane

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of BuLi (2.5 M in hexanes, 22.5 mL, 56.3 mmol) was added over 10 min to a solution of methylphenylsulfone (4.00 g, 25.6 mmol) in THF (70 mL) at 0° C. The solution went from clear to light green to a heterogeneous yellow suspension. The mixture was stirred for 30 min at 0° C. and then chlorodiethylphosphonate (4.46 mL, 30.7 mmol) was added dropwise and the stirring was continued for 30 min, at which point the solution turned clear orange. The reaction mixture was then cooled to −78° C. and oxetan-3-one (1.85 g, 25.6 mmol) was added in THF (3 mL). The reaction mixture turned pale brown/yellow in color. After stirring for another 1.5 h, the reaction mixture was filtered through a plug of silica gel. The filtrate was triturated with solid NH4Cl until pH reached 7. The mixture was then filtered and the filtrate was concentrated. The residue was purified by silica gel chromatography (0-60% EtOAc/heptane) to provide 3-((phenylsulfonyl)methylene)oxetane. 1H NMR (400 MHz, CD2Cl2) δ ppm 7.86-7.99 (m, 2 H) 7.68-7.77 (m, 1 H) 7.57-7.68 (m, 2 H) 6.18 (t, J=2.40 Hz, 1 H) 5.59-5.70 (m, 2 H) 5.30 (td, J=3.41, 2.27 Hz, 2 H)

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