Palladium-Catalyzed Dearomative Allylic Alkylation of Indoles with Alkynes To Synthesize Indolenines with C3-Quarternary Centers

A palladium-catalyzed dearomative allylic alkylation of indoles with alkynes to construct indolenines with C3-quarternary centers was reported. The in situ formed arylallene intermediate omitted the need to install leaving groups on the allylic compounds and employ extra oxidants to oxidize the allylic C–H bonds. The reaction exhibited good functional group tolerance and high atom economy. Moreover, the reaction was further expanded to synthesize pyrroloindolines and furanoindolines

Photoredox Catalysis: Construction of Polyheterocycles via Alkoxycarbonylation/Addition/Cyclization Sequence

A novel visible-light-induced cascade reaction for the preparation of ester-functionalized polyheterocycles was developed under metal-free conditions, which was initiated by an intermolecular radical addition to a carbon–carbon double bond of <i>N</i>-arylacrylamide derivatives using alkyl carbazate as the ester source followed by cyano-mediated cyclization. The desired phenanthridine derivative products were isolated in moderate to high yields with broad substrate scope

Photoredox Catalysis: Construction of Polyheterocycles via Alkoxycarbonylation/Addition/Cyclization Sequence

A novel visible-light-induced cascade reaction for the preparation of ester-functionalized polyheterocycles was developed under metal-free conditions, which was initiated by an intermolecular radical addition to a carbon–carbon double bond of <i>N</i>-arylacrylamide derivatives using alkyl carbazate as the ester source followed by cyano-mediated cyclization. The desired phenanthridine derivative products were isolated in moderate to high yields with broad substrate scope

1,6-Conjugated Addition-Mediated [2+1] Annulation: Approach to Spiro[2.5]octa-4,7-dien-6-one

A formal 1,6-conjugated addition-mediated [2+1] annulation to synthesize spiro[2.5]­octa-4,7-dien-6-one with <i>p</i>-quinone methides and sulfur ylides has been described. This domino-type process was highly diastereoselective and exhibited good functional group tolerance and scalability without the use of metals and bases

1,6-Conjugated Addition-Mediated [2+1] Annulation: Approach to Spiro[2.5]octa-4,7-dien-6-one

A formal 1,6-conjugated addition-mediated [2+1] annulation to synthesize spiro[2.5]­octa-4,7-dien-6-one with <i>p</i>-quinone methides and sulfur ylides has been described. This domino-type process was highly diastereoselective and exhibited good functional group tolerance and scalability without the use of metals and bases

Redox-Neutral Atom-Economic Pd(0)-Catalyzed Dearomatization of β‑Naphthols with Alkynes toward Naphthalenones

A dearomative coupling of β-naphthols with alkynes via Pd hydride catalysis has been developed. This redox-neutral strategy provides a straightforward platform to access diverse naphthalenones bearing congested quarternary stereocenters with excellent atom and step economy since no leaving groups are needed to preinstall on the allylic reagents. The overall utility of this protocol is exemplified by broad functional group compatibility and gram-scale capacity