The preparation of 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

• Bryan Ringstrand,
• Martin Oltmanns,
• Jeffrey A. Batt,
• Aleksandra Jankowiak,
• Richard P. Denicola and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2011, 7, 386–393, doi:10.3762/bjoc.7.49

• olefination of tetrahydro-4H-pyran-4-one gave substituted 4-methylenetetrahydropyrans 6a–6c and 6e in yields ranging from 20–40% (Scheme 8). Methylenetetrahydropyrans 6a and 6b are volatile compounds so again care should be taken during evaporation of solvent to maximize yields. Phosphoranes were generated