Triphenylethylene → 1,1-Dichloro-2,2,3-triphenylcyclopropane

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Reaction Steps

Prepared in 64% yield from 3.2 g (12.5 mmol) of triphenylethylene (3.2 g; 12.5 mmol) and 0.25 g (1.1 mmol) benzyltriethylammonium chloride (TEBA) by dissolving in 50 g (419 mmol) CHCl3, stirring rapidly at room temperature, and treating with 27 mL of chilled 50% aqueous NaOH dropwise according to the method of Dehmlow, E. V., et al., S.S. Phase Transfer Catalysis, Verlag Chemie: Deerfield Beach 1980. After stirring 75 h, the resulting mixture was poured onto 150 mL H2O and extracted with CH2Cl2 (2×100 mL). The combined organic layers were washed with 100 mL H2O, dried (Na2SO4), filtered and concentrated. The resulting brown oil was dissolved in boiling petroleum ether, quickly filtered, and allowed to stand at room temperature, yielding 2.7 g (64%) of Compound 4a as a white powder, mp: 106°-107° C. (petroleum ether) (lit. 105°- 107° C.); NMR δ7.23 (m, 15H, ArH), 3.57 (s, 1H, cyclopropyl H); IR (CM-1) 3020, 3000, 1600, 1490, 1435, 860, 775 765, 750, 695; MS (m/z, % base) 342 (M+4), 3.2; 340 (M+2), 6.3; 338 (M+), 10.23; 303 (--Cl), 100; 267 (--Cl, --HCl), 80.7.

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