20.1 Hz, 1 F, CH 2 F). Ϫ Selected NOEs (CDCl 3 ): {3-H} enhanced (Q, 2 Me), 47.83 (D, C-3), 57.07 (Dd, 3 J C,F ϭ 5.5 Hz, C-4), 62.10 (T, 2 OCH 2 ), 70.90 (D, C-2), 71.76 (Dd, 2 J C,F ϭ 19.0 Hz, C-5), 4-H (2%), 5-H (1%), 2-CH 2 (2%), 1Ј-OCH 2 (0.5%) and 1Ј-CH 2 (1%); {4-H} enhanced 3-H (2%), 5-H (2.5%), 1Ј-H (2.5%), 1Ј-OCH 2 85.44 (Td, 1 J C,F ϭ 170.0 Hz, C-6), 172.11 and 177.52 (S, 2 CO). Ϫ 19 F NMR (CD 3 OD): δ ϭ Ϫ230.75 (dt, J ϭ 21.5 and 47.3 Hz, (1%) and 1Ј-CH 2 (0.5%); {5-H} enhanced 3-H (0.5%), 4-H (2%), and 2-CH 2 (1.5%); {1Ј-H} enhanced 4-H (3%), 2-CH 2 (0.5%), 1Ј-CH 2 F). Ϫ IR (KBr): ν ˜ϭ 3451 cm Ϫ1 , 3341 (ν OH , ν NH ), 1708 (ν COO ). Ϫ MS (FAB/Xe); m/z (%): 282 (25) [M ϩ H] ϩ , 244 (20) OCH 2 (2%) and 1Ј-CH 2 (1%); {2-CH 2 } enhanced 3-H (10.5%), 5-H (9%) and 1Ј-H (2%); {1Ј-OCH 2 } enhanced 3-H (0.5%), 4-H [C 11 H 18 NO 5 ] ϩ , 236 (85) [C 9 H 15 FNO 5 ] ϩ , 218 (63) [C 9 H 13 FNO 4 ] ϩ , 190 (45) [C 8 H 12 O 5 ] ϩ• , 172 (78) [C 7 H 12 O 4 ] ϩ• , 91 (100) [C 3 H 6 FNO] ϩ• . (0.5%) and 1Ј-H (2%); {F} enhanced 3-H (1.5%), 1Ј-H (2.5%), 1Ј-OCH 2 (0.5%) and 1Ј-CH 2 (7.5%). Ϫ IR (film): ν ˜ϭ 2984 cm Ϫ1 , Ϫ C 11 H 20 FNO 6 (281.28): calcd. C 46.97, H 7.17, N 4.98; found C 46.84, H 7.06