Organocatalyzed [4+2] Annulation of All‐Carbon Tetrasubstituted Alkenes with Allenoates: Synthesis of Highly Functionalized 2H‐ and 4H‐Pyran Derivatives.

Abstract A stereoselective [4+2] annulation of acyclic all‐carbon tetrasubstituted alkenes with allenoates was described. The reaction with DABCO proceeded smoothly leading to the formation of highly functionalized 4 H ‐pyran derivatives in good yields. We have also reported first β ‐ICD‐catalyzed [4+2] annulation affording functionalized enantioenriched 2H ‐pyran derivatives bearing a chiral all‐carbon quaternary center.