A new mode of cyclobutenedione ring opening for the synthesis of 2-oxobut-3-enamides and tetrasubstituted furans.

A dichotomy between the additions of organolithiums and lithium amides to cyclobutenediones is described wherein the former give carbonyl addition products while the latter induce ring opening by enone cleavage via O- to C-lithium transfer. This distinct mode of ring scission gives access to 2-oxobut-3-enamides and tetrasubstituted furans.

A Thermally Induced Hydride Transfer from an Amine to an Allene Triggers an Annulation Reaction, Giving Dihydrofuropyridinones.

A thermal rearrangement leading to dihydrofuropyridinones and related polycyclic ring systems from furanones and cyclobutenones is described. A key feature of the reaction is the thermally induced hydride transfer from a 3°-amine to a conjugated allene to trigger cyclization.