Construction of Enantioenriched 4,5,6,7‐Tetrahydrofuro[2,3‐b]pyridines through a Multicatalytic Sequence Merging Gold and Amine Catalysis

Abstract

A series of enantioenriched fused bicyclic piperidines were accessed by a cycloisomerization /cycloaddition strategy. Starting from ynamide derivatives and aldehydes, good yields and high levels of stereoselectivity were obtained through sequential relay catalysis. The concurrent use of a gold complex with a diphenylprolinol silyl ether was applied to a combination of diversely functionalized substrates.

Chemo- and Diastereoselective Cycloisomerization/[2 + 3] Cycloaddition of Enynamides: Synthesis of Spiropyrazolines as Potential Anticancer Reagents

“…Recently, based on the pioneering work from Ma’s group, the gold-catalyzed cycloisomerization of enynamides to generate a dihydrobenzofuran-derived azadiene intermediate has gained much attention for its ability to construct various fused cyclic compounds. , This strategy has been applied in various cascade cycloisomerization/[4 + n ] cycloaddition reactions using different types of reaction partners . For example, in 2019, Chi and co-workers disclosed the Au­(I)/N-heterocyclic carbene (NHC) relay catalytic cycloisomerization/[4 + 2] cyclization reactions of enynamides with enals for the synthesis of furo­[2,3- b ]­pyridine derivatives (Scheme A) .…”

Stereoselective synthesis of functionalized azepines via gold and palladium relay catalysis

“…10 On the basis of dihydrofuran-supported azadienes derived from the cycloisomerization of enynamides 11 reported by Ma, 12 Chi's group reported a gold and N-heterocyclic carbene (NHC) relay catalytic strategy for efficient synthesis of furan-fused six-membered lactams via the [4 + 2] cycloaddition of azadiene intermediates with enals (Scheme 1a). 13 Subsequently, Zhao's group reported a gold/palladium relay catalytic [5 + 4] cycloaddition of azadienes with vinyl ethylene carbonates, 14 which synthesized furan-fused nine-membered heterocycles in high yields and with high enantioselectivities (Scheme 1a). Inspired by these elegant works, we envisioned that the in situ generated dihydrofuran-derived azadienes could be applied in the [4 + 3] cycloaddition of Pd-TMM to access furan-fused azepines.…”

Organocatalyzed Synthesis of Tetrahydro‐α‐Carboline Derivatives Bearing N,O‐Acetals

“…3) [11] . With our continuous interest in enantioselective aminocatalyzed synthesis of polycyclic architectures, [12] we hypothesized that indole‐derived‐1‐azadienes could be engaged in an organocatalyzed one‐pot process to access a family of enantioenriched tetrahydrocarboline scaffolds bearing a hemiaminal functional group (Scheme 1, eq 4).…”