Todd S. McDermott

Synthesis of cyclic and acyclic βγ-unsaturated car☐ylic acids Via an E1-type ionization/elimination of β-lactones

Abstract Cyclic and acyclic ketones were converted in three steps into 3-alkenoic acids, bearing a variety of substituents in the α -position. The sequence, involving ionization/elimination of a β-lactone, affords high yields of pure products uncontaminated with conjugated isomers. Support for an El-type mechanism is also provided.

Sterically guided rearrangement of 3,3-disubstited β-lactones. A rapid construction of cycloheptano trans-fused butyrolactones

Abstract 4-Cyclohexyl 3,3-disubstituted oxetan-2-ones rearrange under Lewis acid catalysis to afford trans-fused cycloheptano butyrolactones.

A New Synthesis of 3-Chloro Butenolides via Rearrangement of 3,3-Dichloro Beta Lactones

Abstract 4,4-Dialkyl 3,3-dichloro oxetan-2-ones rearrange under Lewis acid catalysis, accompanied by loss of HC1, to afford 4,5-dialkyl 3-chloro butenolides. We have recently been investigating the reactions of beta lactones under the influence of Lewis acid catalysis.1 When the lactone ring oxygen is bonded to a secondary carbon atom, a rearrangement occurs in which the beta lactone 1 expands to a butyrolactone 4 with the concommitant migration of a hydrogen or carbon atom into the lactone ring.2 If the oxygen is bonded to a tertiary carbon, an ionization/elimination sequence ensues, producing a β, γ-unsaturated carboxylic acid

A unique 3-chlorobutenolide annulation sequence

Spiro 3,3-dichlorooxetane-2-ones rearrange under Lewis acid catalysis, accompanied by loss of HCl, to afford fused 3-chlorobutenolides in high yield.