Fungicide-inspired precursors of π-allylpalladium intermediates for palladium-catalyzed decarboxylative cycloadditions

Abstract

Inspired by a fungicide, we designed 5-vinyloxazolidine-2,4-diones as new precursor of π-allylpalladium zwitterionic intermediates and developed palladium-catalyzed asymmetric (5+3) cycloaddition with azomethine imines and (3+2) cycloaddition with 1,1-dicyanoalkenes. Both reactions...

Copper‐Catalyzed (3+2) Annulation of 5‐Ethynyloxazolidine‐2,4‐diones with Benzoylacetonitriles: Synthesis of Dihydrofuran Derivatives

“…Initially, various 5-ethynyloxazolidine-2,4-diones were prepared in two steps according to our previous synthetic method for 5vinyl-3,5-diphenyloxazolidine-2,4-diones (Scheme 2; see the Supporting Information for details). [12] We subsequently used Cu(OTf) 2 as a metal catalyst, N, N-diisopropylethylamine (DIPEA) as the base and 1,10-phenanthroline L1 as the ligand in the reaction of 5-ethynyloxazolidine-2,4-dione 1 d and acylacetonitrile 2 a to explore the optimal reaction conditions (Table 1). To our delight, 5-ethynyloxazolidine-2,4-dione 1 d reacted with acylacetonitrile 2 a in the presence of copper catalyst and base in dichloromethane (DCM) to give the (3 + 2) annulation Scheme 2.…”

Palladium-catalyzed regio- and stereoselective allylic alkylation of 5-vinyloxazolidine-2,4-diones with azlactones: synthesis of chiral (Z)-trisubstituted allylic amino acid derivatives

“…Particularly, chiral ligand L6 performed very well in terms of both yield and enantioselectivity (92% yield and 95% ee, entry 6 vs. entries 1-5). Some solvents such as DCE (1,2-dichloroethane), THF, 1,4-dioxane, EtOAc, toluene and m-xylene were next screened at 25 °C (entries [7][8][9][10][11][12]. This investigation led to the finding that DCM is optimal for the process in terms of reactivity and enantioselectivity, giving the desired product 3ak in 92% yield and 95% ee (entry 6 vs. entries 7-12).…”

“…9 Most recently, inspired by a fungicide, we designed 5-vinyloxazolidine-2,4-diones as new precursors of π-allylpalladium zwitterionic intermediates and developed palladium-catalyzed asymmetric (5 + 3) cycloaddition with azomethine imines and (3 + 2) cycloaddition with 1,1-dicyanoalkenes. 10 Obviously, this type of π-allylpalladium intermediate from 5-vinyloxazolidine-2,4-diones will also be workable in asymmetric decarboxylative allylation reactions, according to the principle of decarboxylative allylation reactions. Particularly, when 5-vinyloxazolidine-2,4-diones are used as allyl precursors, an amide moiety will be introduced into the corresponding allylation products.…”

Palladium-Catalyzed Asymmetric (3 + 2) Cycloaddition of 5-Allenyloxazolidine-2,4-Diones with Barbiturate-Derived Alkenes: Synthesis of Spirobarbiturate-γ-Lactams

“…10 Considering the high significance of nitrogen-containing heterocycles in biologically active natural products and pharmaceuticals, our group also developed 5-vinyloxazolidine-2,4-diones as nitrogen-containing π-allyl palladium zwitterion precursors, which achieved asymmetric (5 + 3) cycloaddition with azomethine imines and (3 + 2) cycloaddition with 1,1-dicyanoalkenes respectively (Scheme 1a). 11 Combining the structures of the two precursors above, we are interested in developing precursors for nitrogen-containing π- At the outset of our experiments, we chose barbituratederived alkene 1a and 5-allenyloxazolidine-2,4-dione 2a (1.2 equiv) as model substrates (Table 1). When the combination of Pd 2 (dba) 3 •CHCl 3 with PPh 3 was used as the catalyst, the formal (3 + 2) annulation between 1a and 2a proceeded smoothly in CH 2 Cl 2 at 25 °C to give the product 3aa in 64% yield with good diastereoselectivity (entry 1).…”

“…In 2021, our group developed a Pd-catalyzed (3 + 3) annulation reaction of AECs with nitrile oxides to afford six-membered heterocycles bearing an allenyl group (Scheme a) . Considering the high significance of nitrogen-containing heterocycles in biologically active natural products and pharmaceuticals, our group also developed 5-vinyloxazolidine-2,4-diones as nitrogen-containing π-allyl palladium zwitterion precursors, which achieved asymmetric (5 + 3) cycloaddition with azomethine imines and (3 + 2) cycloaddition with 1,1-dicyanoalkenes respectively (Scheme a) . Combining the structures of the two precursors above, we are interested in developing precursors for nitrogen-containing π-allenyl palladium zwitterions.…”