A novel method for the preparation of the spirocyclic Δβ,γ-butenolides is presented. The developed strategy is based on a trienamine-mediated [4+2]-cycloaddition between (E)-3-alkylidene- 5-arylfuran-2(3H)-ones and ...

Quaternary amino acids containing a geminal bisphosphonate moiety have been synthesized for the first time. The developed two-step reaction sequence utilizes the Michael addition of α-substituted azlactones to a vinylidene ...