[4 + 2]-Annulations of Aminocyclobutanes
journal contributionposted on 20.02.2015, 00:00 by Daniele Perrotta, Sophie Racine, Jeremy Vuilleumier, Florian de Nanteuil, Jerome Waser
The first [4 + 2]-annulation between aminocyclobutanes and aldehydes to access tetrahydropyranyl amines is reported. With phthalimido cyclobutane dicarboxylates and aromatic aldehydes, tetrahydropyrans were obtained in 53–92% yield and 3:1–17:1 dr using scandium triflate or iron trichloride as catalyst. The use of thymine- or fluorouracil-substituted cyclobutanes gave direct access to six-membered ring nucleoside analogues. Finally, the [4 + 2]-annulation between aminocyclobutanes and enol ethers led to the corresponding cyclohexylamines.