Unusual Olefin Formation by PhSe-F trans-Elimination

Abstract

A new approach to the synthesis of 2′,3′-didehydro-2′,3′-dideoxynucleosides was described in excellent yield through unusual olefin formation by PhSe-F trans-elimination.

Keywords:

• Nucleoside
• HBV
• HIV
• Elimination

Notes

*Compound 7: ¹H NMR (400 MHz, DMSO-d ₆) δ 7.94 (d, J = 8.4 Hz, 2H, 2Bz-H), 7.90 (d, J = 7.2 Hz, 1H, H-6), 7.62 (d, J = 8.4 Hz, 2H, 2Bz-H), 6.20 (d, J = 6.0 Hz, 1H, H-1′), 5.88 (d, J = 8.0 Hz, 1H, H-5), 5.72 (m, 1H, H-2′), 5.61 (dm, J = 56.0 Hz, 1H, H-3′), 4.65 (m, 1H, H-4′), 5.59 (dd, J = 4.4, 12.0 Hz, 1H, H-5′), 4.40 (dd, J = 8.0, 12.0 Hz, 1H, H-5”). Anal Calcd for C₁₆H₁₂ClFN₂O₅: C, 52.40; H, 3.30; N, 7.64. Found: C, 52.19; H, 3.35; N, 7.65.

^†Compound 9: ¹H NMR (400 MHz, DMSO-d ₆) δ 11.40 (s, 1H, D₂O exchangeable, NH), 7.94 (d, J = 8.0 Hz, 2H, 2Bz-H), 7.64 (d, J = 6.8 Hz, 2H, 2Bz-H), 7.34 (d, J = 8.8 Hz, 1H, H-6), 6.82 (m, 1H, H-1′), 6.53 (d, J = 6.0 Hz, 1H, H-3′), 6.05 (d, J = 6.0 Hz, 1H, H-2′), 5.28 (d, J = 8.4 Hz, 1H, H-5), 5.12 (br s, 1H, H-4′), 4.55 (dd, J = 3.2, 12.0 Hz, 1H, H-5′), 4.45 (dd, J = 5.2, 12.0 Hz). Anal Calcd for C₁₆H₁₃ClN₂O₅· 1/4H₂O: C, 54.35; H, 3.75; N, 7.92. Found: C, 54.31; H, 3.81; N, 7.85.