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0 °C

1-(6-Chloro-2,3-dihydrobenzo[b][1,4]dioxin-8-yl)ethanone (248 mg, 1.17 mmol), titanium(IV) isopropoxide (0.84 mL, 2.33 mmol) and 2 M solution of ammonia in ethanol (2.90 mL, 5.83 mmol) were stirred at room temperature for 6 h. The reaction was cooled to 0° C. and sodium borohydride was added portionwise during 10 min. (0.66 mg, 1.76 mmol); the resultant mixture was stirred at rt for an additional 3 h. The reaction was quenched by pouring it into ammonium hydroxide (2 M, 20 mL), the precipitate that formed was filtered off and washed with ethyl acetate (10 mL×3). The organic layer was separated and the remaining aqueous layer was extracted with ethyl acetate (10 mL×2). The combined organic extracts were washed with 1 M HCl (10 mL). The acidic aqueous extracts were washed with ethyl acetate (25 mL), then treated with aqueous sodium hydroxide (2 M) to pH 10-12, and extracted with ethyl acetate (25 mL×3). The combined organic extracts were washed with brine (10 mL), dried (Na2SO4), and concentrated in vacuo to afford the desired product (130 mg, 61% yield). 1H NMR (400 MHz, CDCl3): δ 6.87 (d, 1H), 6.75 (d, 1H), 4.24 (m, 5H), 1.35 (d, 3H).

1. customThe reaction was quenched
2. additionby pouring it into ammonium hydroxide (2 M, 20 mL)
3. customthe precipitate that formed
4. filtrationwas filtered off
5. washwashed with ethyl acetate (10 mL×3)
6. customThe organic layer was separated
7. extractionthe remaining aqueous layer was extracted with ethyl acetate (10 mL×2)
8. washThe combined organic extracts were washed with 1 M HCl (10 mL)
9. washThe acidic aqueous extracts were washed with ethyl acetate (25 mL)
10. additiontreated with aqueous sodium hydroxide (2 M) to pH 10-12
11. extractionextracted with ethyl acetate (25 mL×3)
12. washThe combined organic extracts were washed with brine (10 mL)
13. dry with materialdried (Na2SO4)
14. concentrationconcentrated in vacuo