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 volatilecompounds so again care should be taken during evaporation of solvent to maximize yields. Phosphoranes were generated
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Graphical Abstract
Figure 1:
Methods for synthesis of dibromides I and their use for preparation of 6-membered heterocycles.