反应详情

To a solution of SOCl2 (5.7 mL, 2.5 eq) in dry CH3CN (37 mL) under argon was cooled to −40° C. was added tert-butyl 2-(3-bromophenyl)-1-hydroxypropan-2-ylcarbamate (DC3; R4=Me) (10.3 g, 31 mmol) in dry CH3CN (27 mL) was added dropwise, followed by the addition of dry pyridine (12.4 mL, 160 mmol, 5 eq). The mixture was then allowed to warm to RT in 1 h. The mixture was concentrated to about 30 mL. EtOAc (30 mL) was added and the precipitate was filtered off. The filtrate was concentrated in vacuo to give 10.4 g (89%) of 3-(tert-butoxycarbonyl)-4-(3-bromophenyl)-4-methyl-[1,2,3]-oxathiazolidine-2-oxide as a colorless oil. 1H NMR (CDCl3) δ 7.64 (t, J=2.0 Hz, 1H), 7.36-7.53 (m, 2H), 7.24 (m, 1H), 4.52 (q, J=9.5 Hz, 2H), 1.86 (s, 3H), 1.42 (br s, 9H).

1. additionwas added dropwise
2. concentrationThe mixture was concentrated to about 30 mL
3. additionEtOAc (30 mL) was added
4. filtrationthe precipitate was filtered off
5. concentrationThe filtrate was concentrated in vacuo