New Routes to Pyranotetrahydrofuran Derivatives

The determination of the structure of (4aRS,4bSR,6RS,8aRS,9aSR)-6-methyl-3,4,4a,4 b,5,6,7,8,8a,9a-decahydro-2H-benzofuro[2,3-b]pyran, C₁₂H₂₀O₂, has allowed us to interpret the stereochemistry of the elimination-addition process by which the compound is obtained from the reaction of 3-bromodihydropyran with ketone enolate and sodium amide. The conformation of the molecule in the solid state is discussed and compared with the conformation calculated by molecular-mechanics optimization.

-1