Ynamides are special alkynes bearing an electron-withdrawing group on the nitrogen atom, and they have been extensively studied over past decade. However, addition of functional groups across ynamides in these transformations typically occurs at α-position ynamide because strong polarization alkynyl moiety. Studies umpolung chemistry may not only discover organic reactions but also lead to divergent syntheses, thus significantly enriching chemistry. This review summarizes four main...

An efficient yttrium-catalyzed intramolecular hydroalkoxylation/Claisen rearrangement sequence has been achieved, thus enabling facile access to a diverse array of valuable medium-sized lactams. Furthermore, mechanistic rationale for this novel cascade reaction is well supported by variety control experiments.

Abstract Platinum‐catalyzed formal [5+2] and [4+2] annulations of isoxazoles with heterosubstituted alkynes enabled the atom‐economical synthesis valuable 1,3‐oxazepines 2,5‐dihydropyridines, respectively. Importantly, this Pt catalysis not only led to unique reactivity dramatically divergent from that observed under Au catalysis, but also proceeded via unprecedented α‐imino platinum carbene intermediates.

The generation of metal-containing 1,3-dipoles from metal carbenes represents a significant advance in 1,3-dipolar cycloaddition reactions. However, these transformations have so far been limited to reactions based on diazo compounds or triazoles as precursors. Herein, we disclose copper-catalyzed enantioselective reaction alkenyl N-propargyl ynamides with styrene derivatives by formal [3 + 2] via Cu-containing all-carbon 1,3-dipoles, which constitutes novel way for the carbenes. This...

Here, we report a copper-catalyzed asymmetric cascade cyclization/[1,2]-Stevens-type rearrangement via non-diazo approach, leading to the practical and atom-economic assembly of various valuable chiral chromeno[3,4-c]pyrroles bearing quaternary carbon stereocenter in generally moderate good yields with wide substrate scope excellent enantioselectivities (up 99 % ee). Importantly, this protocol not only represents first example catalytic [1,2]-Stevens-type based on alkynes but also...

Carbonyl ylides have proven to be powerful synthons for the efficient construction of various valuable O-heterocycles, and formation carbonyl by reaction metal carbenes with carbonyls has attracted increasing attention over past decades. However, a catalyst-controlled highly enantioselective from is extremely challenging. Herein, we report novel copper-catalyzed asymmetric formal [2+1] [4+1] annulations diynes ketones via ylides. Importantly, this protocol not only represents first example...

Medium-sized N,S-heterocycles have received tremendous interest due to their biological activities and potential medical applications. However, asymmetric synthesis of these compounds are extremely rare. Described herein is a catalyst-dependent [3,3]-sigmatropic rearrangement sulfoxide-ynamides, enabling divergent atom-economic series valuable medium-sized in moderate good yields with broad substrate scope. Importantly, excellent enantioselectivities been achieved via an unprecedented...

A metal-free intramolecular tandem sequence involving alkoxylation, Claisen rearrangement and lactone expansion has been achieved.

A copper-catalyzed asymmetric cyclization of alkenyl diynes involving a vinylic C(sp²)–H functionalization is reported, enabling the construction various valuable chiral polycyclic-pyrroles in high yields and enantioselectivities.

6π electrocyclization has attracted interest in organic synthesis because of its high stereospecificity and atom economy the construction versatile 5-7-membered cycles. However, examples asymmetric are quite scarce, have to rely on use chiral organocatalysts, been limited pentadienyl-anion- triene-type electrocyclizations. Described herein is a zinc-catalyzed formal [4+3] annulation isoxazoles with 3-en-1-ynol ethers via electrocyclization, leading site-selective functionalized 2H-azepines...

A zinc-catalyzed formal [3 + 2] annulation of isoxazoles with ynol ethers has been developed, leading to the atom-economical and divergent synthesis 2-alkoxyl 1<italic>H</italic>-pyrroles 3<italic>H</italic>-pyrroles, respectively.

Abstract An efficient yttrium‐catalyzed intramolecular hydroalkoxylation/Claisen rearrangement sequence has been achieved, thus enabling facile access to a diverse array of valuable medium‐sized lactams. Furthermore, mechanistic rationale for this novel cascade reaction is well supported by variety control experiments.

Abstract Platinum‐catalyzed formal [5+2] and [4+2] annulations of isoxazoles with heterosubstituted alkynes enabled the atom‐economical synthesis valuable 1,3‐oxazepines 2,5‐dihydropyridines, respectively. Importantly, this Pt catalysis not only led to unique reactivity dramatically divergent from that observed under Au catalysis, but also proceeded via unprecedented α‐imino platinum carbene intermediates.

A novel zinc-catalyzed reaction of isoxazoles with thioynol ethers involving an unprecedented 1,2-sulfur migration has been developed.

A metal-free intramolecular alkoxylation-initiated cascade cyclization of allyl ether-tethered ynamides has been developed, leading to functionalized 3-isochromanones in high yields.

Büchner reaction, as an exclusive category of expansive dearomatization, represents a powerful approach for the construction valuable functionalized cycloheptatrienes in direct manner from readily available aromatic precursors. However,...

A novel Brønsted acid-catalyzed oxidative C-H functionalization of alkynyl thioethers has been developed. This method allows the practical synthesis valuable isothiochroman-3-ones in mostly moderate to good yields under mild reaction conditions and features a broad substrate scope wide functional group tolerance. Moreover, this metal-free oxidation can also be used promote formal N-H insertion involving an unexpected 1,2-sulfur migration, affording useful 1,4-benzothiazin-3-ones.