Chiron approach for the synthesis of (5RS)-Hagen’s gland lactones from diacetone-d-mannose

A new and convergent synthetic route for (5RS)-Hagen’s lactones 1–4 is described, starting from bisacetonide mannofuranolactone 5. The key transformations in the synthesis are SmI2 mediated α-deoxygenation of a aldonolactone to 2-deoxy lactone, Pd(II) mediated oxidative cyclization and an oxidation of tetrahydrofuran to a furanone.

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2,2-Dimethyl-6-vinyl-dihydrofuro-[3,4-d][1,3]dioxal-4-oneC9H12O4[α]D21=+31.9 (c 0.8, CHCl3)Source of chirality: d-mannose

4-Hydroxy-5-vinyl-dihydro-furan-2-oneC6H8O3[α]D21=+21.5 (c 1.0, CHCl3)Source of chirality: d-mannose

Hex-5-ene-1,3,4-triolC6H12O3[α]D21=+9.1 (c 0.5, D2O)Source of chirality: d-mannose

2-Vinyl-tetrahydro-furan-3-olC6H10O2[α]D21=+26.1 (c 0.85, CHCl3)Source of chirality: d-mannose