A novel catalytic decarbonylative Heck-type reaction and conjugate addition of aldehydes to unsaturated carbonyl compounds

A visible-light-induced photosensitizer-free decarbonylative Minisci-type reaction

This study presents a green and practical visible-light-induced photosensitizer-free decarbonylative Minisci-type reaction using aldehydes as alkyl radical precursors. The photocatalytic system exhibits a broad substrate scope and synthetically useful yields. Mechanistic experiments revealed that alkyl radicals could be generated through auto-oxidation of aldehydes under irradiation, which is a mild and effective method for achieving late-stage functionalization of N-heteroarenes. Some biologically active N-heteroarenes could be alkylated using this photocatalytic system smoothly.

Ru(II)-Catalyzed Decarbonylative Alkylation and Annulations of Benzaldehydes with Iodonium Ylides under Chelation Assistance

A Ru(II)-catalyzed decarbonylative alkylation and annulation of salicylaldehydes and 2-aminobenzaldehydes with iodonium ylides has been developed for the synthesis of dibenzo[b,d]furans and NH-free carbazolones. The reaction proceeds smoothly under mild conditions with a low catalyst loading and a broad substrate compatibility. Notably, hydroxy and free amino groups were demonstrated to be the effective directing groups, enabling the successful aldehyde C-H bond activation and subsequent decarbonylation and annulation under the inexpensive Ru(II) catalyst.

Cu-Catalyzed alkylation-cyanation type difunctionalization of styrenes with aliphatic aldehydes and TMSCN via decarbonylation

A copper-catalyzed decarbonylative alkylation-cyanation of styrene derivatives with aliphatic aldehydes and trimethylsilyl cyanide to provide chain elongated nitriles is reported. Using TBHP as an oxidant and free radical initiator, the reaction can smoothly convert abundant α-di-substituted, α-mono-substituted and linear aliphatic aldehydes into the corresponding 3°, 2° and 1° alkyl radicals to initiate the subsequent radical-type difunctionalization of various styrenes.

DFT study on the ruthenium-catalyzed decarbonylative annulation of an alkyne with a six-membered hydroxychromone via C–H/C–C activation

Both steady-state approximation and the modified energy span model have been employed to determine the TOF-determining transition state and TOF-determining intermediate for the title catalytic reaction.

Mizoroki-Heck Reaction of Unstrained Aryl Ketones via Ligand-Promoted C-C Bond Olefination

Mizoroki-Heck reaction of unstrained aryl ketone with acrylate/styrene is accomplished via palladium-catalyzed ligand-promoted C-C bond cleavage. Various (hetero)aryl ketones are compatible in the reaction, affording the alkene product in good to excellent yields. Further applications in the late-stage olefination of some drugs, natural products, and fragrance-derived aryl ketones demonstrate the synthetic utility of this protocol. By employing ketone as both the directing group and the leaving group, 1,2-bifunctionalization is achieved via sequential ortho-C-H alkylation/ipso-Heck olefination.

Fe-catalyzed Decarbonylative Alkylative Spirocyclization of N-Arylcinnamamides: Access to Alkylated 1-Azaspirocyclohexadienones

For the convenient introduction of simple linear/branched alkyl groups into biologically important azaspirocyclohexadienones, a practical Fe-catalyzed decarbonylative cascade spiro-cyclization of N-aryl cinnamamides with aliphatic aldehydes to provide alkylated 1-azaspiro-cyclohexadienones was developed. Aliphatic aldehydes were oxidative decarbonylated into primary, secondary and tertiary alkyl radicals conveniently and allows for the subsequent cascade construction of dual C(sp3)-C(sp3) and C=O bonds via radical addition, spirocyclization and oxidation sequence.

Fe-Catalyzed decarbonylative cascade reaction of N-aryl cinnamamides with aliphatic aldehydes to construct 3,4-dihydroquinolin-2(1H)-ones

A practical Fe-catalyzed decarbonylative cascade reaction of N-aryl cinnamamides with aliphatic aldehydes to provide C3 alkylated 3,4-dihydroquinolin-2(1H)-ones is developed. Aliphatic aldehydes were oxidatively decarbonylated into 1°, 2° and 3° alkyl radicals conveniently, allowing for the subsequent cascade construction of C(sp3)-C(sp3) and C(sp3)-C(sp2) bonds via radical addition and HAS-type cyclization. The importance of the amide linkage and the selectivity of the 6-endo-trig over 5-exo-trig cyclization pathway were elucidated by experimental results and DFT calculations.

Rh-Catalyzed intramolecular decarbonylative cyclization of ortho-formyl group tethered alkylidenecyclopropanes (ACPs) for the construction of 2-methylindenes

A Rh-catalyzed intramolecular cascade decarbonylative coupling reaction of ortho-formyl group-tethered alkylidenecyclopropanes has been developed, affording indene derivatives in moderate to good yields.

Regio- and stereo-selective decarbonylative alkylative arylation of terminal alkynes with aliphatic aldehydes and arenes via dual C–H bond functionalization

Readily available linear/branched aliphatic aldehydes including sugar derivatives were oxidatively decarbonylated into 1˙, 2˙ and 3˙ alkyl radicals for the alkylative arylation of terminal alkynes via dual C–H bond functionalization.

Co-Catalyzed decarbonylative alkylative esterification of styrenes with aliphatic aldehydes and hypervalent iodine(iii) reagents

Decarbonylation of aliphatic aldehydes into 1°, 2° and 3° alkyl radicals to construct C(sp³)–C(sp³) bond via radical addition and C(sp³)–O bond via the interconversion of Co^II–Co^III–Co^I.

Metal-free decarbonylative alkylation-aminoxidation of styrene derivatives with aliphatic aldehydes and N-hydroxyphthalimide

A convenient metal-free decarbonylative alkylation-aminoxidation of styrene derivatives with aliphatic aldehydes and N-hydroxyphthalimide (NHPI) to yield phthalimide protected alkoxyamines is developed. With DTBP as an oxidant and radical-initiator, this reaction smoothly converts aliphatic aldehydes into alkyl radicals and subsequently allows the cascade construction of C(sp³)-C(sp³) and C(sp³)-O bonds via radical-radical coupling.

Fe-Catalyzed radical-type difunctionalization of styrenes with aliphatic aldehydes and trimethylsilyl azide via a decarbonylative alkylation–azidation cascade

A three-component oxidative decarbonylative alkylation–azidation cascade reaction of styrene derivatives with aliphatic aldehydes and TMSN₃ to provide aliphatic azides is developed.

Metal-free oxidative decarbonylative coupling of aromatic aldehydes with arenes: direct access to biaryls

A metal-free oxidative decarbonylative coupling of aromatic aldehydes with electron-rich or electron-deficient arenes to produce biaryl compounds was developed. This novel coupling was proposed to proceed via a non-chain radical homolytic aromatic substitution (HAS) type mechanism, based on the substrate scope, ortho-regioselectivity, radical trapping experiments and DFT calculation studies. With the ready availability of aromatic aldehydes and arenes, metal-free conditions should make this coupling attractive for the biaryl synthesis.

Rhodium-catalyzed oxidative decarbonylative Heck-type coupling of aromatic aldehydes with terminal alkenes

A rhodium-catalyzed oxidative decarbonylative Heck-type coupling of aromatic aldehydes and terminal alkenes to afford 1,2-disubstituted alkenes with good regio- and E-selectivity is developed.

Phosphine ligand triggered oxidative decarbonylative homocoupling of aromatic aldehydes: selectively generating biaryls and diarylketones

A novel rhodium-catalyzed oxidative decarbonylative homocoupling of aromatic aldehydes to generate biaryls and diarylketones selectively and efficiently, triggered by the choice of different phosphine ligands.