Visible-Light-Mediated Strategies to Assemble Alkyl 2-Carboxylate-2,3,3-Trisubstituted β-Lactams and 5-Alkoxy-2,2,4-Trisubstituted Furan-3(2H)-ones Using Aryldiazoacetates and Aryldiazoketones

Abstract

Two new visible-light-mediated strategies are described starting from aryldiazoacetates. The first approach describes their reaction with azides to afford the corresponding imines, and then reaction with aryldiazoketones produces alkyl 2carboxylate-2,3,3-trisubstituted β-lactams. The second approach describes the reaction with sulfoxides to afford the corresponding sulfoxonium ylides, followed by reaction with aryldiazoketones to produce 5-alkoxy-2,2,4-trisubstituted furan-3(2H)-ones. These protocols take advantage of the photolysis of aryldiazoacetates and the photochemically promoted Wolff rearrangement of aryldiazoketones.

Synthesis of β-Lactams through Carbonylation of Diazo Compounds Followed by the [2 + 2] Cycloaddition Reaction

“…Later, 2 mL (0.25 M) of double-distilled DCM was added in a swift, and the reaction tube was sealed, followed by stirring of the reaction mixture at rt for 4–6 h until the reaction gets over. The crude reaction mixture was evaporated for the solvent and purified by column chromatography using hexane and ethyl acetate (95:5) as the eluent on a silica gel 100–200 mesh size to yield the corresponding product ( 3a–3g and 4a–4v ). − …”

“…27,28 Munaretto et al proposed a bluelight-mediated 29 two step reaction of aryldiazoacetates with azides to afford the corresponding imines, which further reacted with aryldiazoacetates to yield corresponding β-lactams (Figure 2b). 30 Poteat et al reported α-hydroxylation of sulfonylcyclopropanes to form cyclopropanone, which further undergoes [3 + 1] cycloaddition with hydroxylamines to produce chiral β-lactams (Figure 2c). 31 Feroci et al explained an electrochemical strategy where deprotonation β-bromopropionanilide at the N−H position (alpha to the carbonyl group) followed by internal bromide displacement produced βlactam.…”

Visible-Light-Mediated Formal Carbene Insertion Reaction: Enantioselective Synthesis of 1,4-Dicarbonyl Compounds Containing All-Carbon Quaternary Stereocenter

“…With the reemergence of photochemical carbene transfer reactions, free carbene species can be easily formed in the absence of metal catalysts . Photochemical carbene transfer reactions, which were used as an efficient synthetic tool, have been applied in cycloaddition reactions, rearrangement reactions, X–H bond insertion reactions, and coupling reactions . Even though the use of light can avoid high temperatures and metal catalysts, the reaction types with free carbene intermediates are limited.…”

Asymmetric Three-Component Reaction of Two Diazo Compounds and Hyrdroxylamine Derivatives for the Access to Chiral α-Alkoxy-β-amino-carboxylates

“…However, hydroxylamine derivatives, such as isoxazole, oxime, and azirine, could react with metal carbene species for the gem -aminohydroxylation on the carbene center through a N–O bond insertion reaction (Scheme b) . Moreover, a variety of nitrogen sources have been reported as effective reagents for the metal carbene imination. − Recently, Sun and co-workers have reported a CN bond formation reaction of a metal carbene intermediate with N -hydroxyaniline as the nitrogen source, providing a concise approach for the synthesis of ketimines which are difficult to access by other methods (Scheme c) . Inspired by these works and as an extension of our research interest in an asymmetric multicomponent reaction via electrophilic interception of an in situ generated intermediate, , we herein report a conceptually distinct three-component asymmetric formal aminohydroxylation of two diazo compounds with hydroxylamine derivatives via Rh 2 (OAc) 4 and chiral phosphoric acid (CPA) cooperative catalysis.…”