Olefination of Electron-Deficient Alkenes with Allyl Acetate: Stereo- and Regioselective Access to (2<i>Z</i>,4<i>E</i>)‑Dienamides

A Ru-catalyzed direct olefination of electron-deficient alkenes with allyl acetate via C–H bond activation is disclosed. By using <i>N</i>,<i>N</i>-disubstituted aminocarbonyl as the directing group, this external oxidant-free protocol resulted in high reaction efficiency and good stereo- and regioselectivities, which opens a novel synthetic passway for access to (<i>Z</i>,<i>E</i>)-butadiene skeletons

Copper-Catalyzed Oxidative Cyclization of 2‑Amino-azaarenes with Lignin Models: Synthesis of 3‑Phenoxy Imidazo Heterocycles

A catalytic oxidative cyclization of 2-aminopyridines or 2-aminobenzothiazole with 2-phenoxyacetophenones (a kind of lignin platform compound) was developed, efficiently providing valuable 3-phenoxy imidazo­[1,2-<i>a</i>]­pyridines or 3-phenoxy benzo­[<i>d</i>]­imidazo­[2,1-<i>b</i>]­thiazoles. The reaction was realized under oxygen by simply using inexpensive CuI as the catalyst

Synthesis of Cyano-Containing Phenanthridine Derivatives via Catalyst‑, Base‑, and Oxidant-Free Direct Cyanoalkylarylation of Isocyanides

An efficient catalyst-, base-, and oxidant-free direct cyanoalkylarylation of isocyanides with AIBN has been developed under mild conditions. This strategy provides an elusive and rapid access to a wide range of cyano-containing phenanthridine derivatives in good yields via a one-pot alkylation/cyclization radical-cascade process. The mild reaction conditions together with no need of any catalyst, base, or oxidant make this protocol environmentally benign and practical

<i>N</i>-Heterocyclic Carbene (NHC)-Catalyzed Highly Diastereo- and Enantioselective Oxo-Diels–Alder Reactions for Synthesis of Fused Pyrano[2,3-<i>b</i>]indoles

A chiral <i>N</i>-heterocyclic carbene (NHC)-catalyzed Diels–Alder reaction of 2-oxoindolin-3-ylidenes and α-chloroaldehydes was developed for the synthesis of fused pyrano[2,3-<i>b</i>]indoles in good to excellent yields (up to 99%) with high <i>cis</i>-diastereoselectivities (>99:1 <i>dr</i>) and enantioselectivities (up to >99% <i>ee</i>)

N‑Heterocyclic Carbene/Lewis Acid Catalyzed Enantioselective Aerobic Annulation of α,β-Unsaturated Aldehydes with 1,3-Dicarbonyl Compounds

A novel and efficient aerobic asymmetric cyclization reaction of cinnamaldehydes and 1,3-dicarbonyl compounds through oxidative NHC-catalysis has been developed, and it allows the synthesis of a wide range of enantiomeric enriched dihydropyranone derivatives in good yields with good to excellent enantioselectivities. Various α,β-unsaturated aldehydes with aliphatic and aromatic substitution groups and 1,3-dicarbonyl compounds were well tolerated. The air was directly used as the oxidant, which made this asymmetric cyclization reaction in a highly efficient, cheap, and green manner

Amide Directed Cross-Coupling between Alkenes and Alkynes: A Regio- and Stereoselective Approach to Substituted (2<i>Z</i>,4<i>Z</i>)‑Dienamides

A ruthenium-catalyzed direct cross-coupling between alkenes and alkynes via directed C–H bond activation is described. By using <i>N</i>,<i>N</i>-disubstituted aminocarbonyl as a directing group, this oxidant-free and atom-economic protocol resulted in high efficiency and good stereoselectivities, which opens a novel synthetic passway for access to substituted (<i>Z</i>,<i>Z</i>)-butadiene skeletons

N‑Heterocyclic Carbene-Catalyzed Asymmetric Benzoin Reaction in Water

A chiral N-heterocyclic carbene-catalyzed benzoin condensation reaction in water has been developed, affording α-hydroxy ketones in good to high yields and high enantioselectivities. Water was proposed as a proton shuttle in the aqueous asymmetric condensation reaction

Asymmetric NHC-Catalyzed Aza-Diels–Alder Reactions: Highly Enantioselective Route to α‑Amino Acid Derivatives and DFT Calculations

A facile <i>N</i>-heterocyclic carbene catalytic enantioselective aza-Diels–Alder reaction of oxodiazenes with α-chloroaldehydes as dienophile precursors is reported, with excellent enantioselectivity (ee > 99%) and excellent yield (up to 93%). DFT study showed that <i>cis</i>-<b>TSa</b>, formed from a top face approach of oxodiazene to <i>cis</i>-<b>IIa</b>, is the most favorable transition state and is consistent with the experimental observations

Asymmetric NHC-Catalyzed Aza-Diels–Alder Reactions: Highly Enantioselective Route to α‑Amino Acid Derivatives and DFT Calculations

A facile <i>N</i>-heterocyclic carbene catalytic enantioselective aza-Diels–Alder reaction of oxodiazenes with α-chloroaldehydes as dienophile precursors is reported, with excellent enantioselectivity (ee > 99%) and excellent yield (up to 93%). DFT study showed that <i>cis</i>-<b>TSa</b>, formed from a top face approach of oxodiazene to <i>cis</i>-<b>IIa</b>, is the most favorable transition state and is consistent with the experimental observations

Rapid Access to Spirocylic Oxindoles: Application of Asymmetric N‑Heterocyclic Carbene-Catalyzed [3 + 3] Cycloaddition of Imines to Oxindole-Derived Enals

A chiral N-heterocyclic carbene (NHC)-catalyzed [3 + 3] cycloaddition reaction of imines and oxindole-derived enals was developed for rapid access to spirocylic oxindoles. In most cases, the desired spirocylic oxindole products were obtained in high yields and excellent enantioselectivities with less than 1 h of reaction time