6533b86efe1ef96bd12cbe22
RESEARCH PRODUCT
Controlled rearrangement of lactam-tethered allenols with brominating reagents: a combined experimental and theoretical study on α- versus β-keto lactam formation.
Manuel ArnóAmparo LunaLuis R. DomingoSara CembellinSara CembellínBenito AlcaidePedro Almendrossubject
Reaction mechanismLactamsMolecular StructureStereochemistryChemistryOrganic ChemistryStereoisomerismGeneral ChemistryTetramic acidModels TheoreticalRing (chemistry)beta-LactamsCatalysisAdductAlkadieneschemistry.chemical_compoundReagentLactamIndicators and ReagentsChemoselectivityBond cleavageBromosuccinimidedescription
N-Bromosuccinimide (NBS) smoothly promotes the ring expansion of lactam-tethered allenols to efficiently afford cyclic α- or β-ketoamides with good yields and high chemo-, regio-, and diastereoselectivity, through controlled C-C bond cleavage of the β- or γ-lactam nucleus. Interestingly, in contrast to the rearrangement reactions of 2-azetidinone-tethered allenols, which lead to the corresponding tetramic acid derivatives (β-keto lactam adducts) as the sole products, the reactions of 2-indolinone-tethered allenols under similar conditions give quinoline-2,3-diones (α-keto lactam adducts) as the exclusive or major products. To rationalize the experimental observations, theoretical studies have been performed.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-04-15 | Chemistry (Weinheim an der Bergstrasse, Germany) |