Cp*Co^III‐Catalyzed Bis‐isoquinolone Synthesis by C−H Annulation of Arylamide with 1,3‐Diyne

Abstract

Cp*Co -catalyzed highly regioselective mono- and bis-annulation of arylamides with 1,3-diynes using N-OMe as an internal oxidant is demonstrated. This atom-economical transformation does not require any external oxidant and tolerates many functional groups. Various symmetrical and unsymmetrical heterocycles (homo and hetero) are accessed with predictable regio- and chemoselectivity.

Rhodium‐Catalyzed Copper‐Assisted Intermolecular Domino C−H Annulation of 1,3‐Diynes with Picolinamides: Access to Pentacyclic π‐Extended Systems

“…1,3-Diynes have the potential to provide further complexity; however,t he limited number of methodse xploiting1 ,3-diynes in CÀHa nnulation highlightst he challenges of regiocontrol in the insertion and mono/diannulations electivity. [11][12][13] In ap ioneering example, Glorius and co-workers demonstrated the Rh III -catalyzed diannulationo fb enzamides with 1,3-diynes leadingt ob iheterocycles (Scheme 1d). [11] This approach has since been extended to cobalt catalysis.…”

“…[11] This approach has since been extended to cobalt catalysis. [12] Althoughi nt hese transformations each p system of the diyne undergoes migratory insertion independently of the other,w eq uestioned whether an alternative mechanism would be possible in which the 1,3-diyne could engage both alkyne motifs in an orchestrated sequence of insertion events, thereby enabling the access to new polycyclic aromatic architectures. During the final stages of our investigations,Chalifoux and co-workers reported the first realizationo ft his goal, namely the dominob enzannulation reaction of 1,3-diynes.…”

“…Although we were aware that controlling the regioselectivity in each of the four alkyne migratory insertions would present an immediate significant challenge, previous success in the control of regioselectivity in 1,3-diyned iannulationb yG loriusa nd others offered hope that theseo bstacles would not be insurmountable. [11,12] Herein, we present am ethod for the rhodium-catalyzed oxidative intermolecular annulation of picolinamides with two molecules of diaryl-1,3-diyne in which the four alkyne units participate in annulation, thereby enabling the assembly of up to four fused rings with extended p conjugation in as ingle step through ad ouble CÀHb ond activation and the construction of five CÀCb onds. Interestingly,t hrought he appropriate choiceo fr eactionc onditions, either isoquinoline-1-carboxamides or fused polycyclic systems can be obtained selectively through as witch in the regioselectivity of the second diyne insertion.…”

Cp*CoIII‐Catalyzed Efficient Dehydrogenation of Secondary Alcohols

“…[10] Alarge variety of reactions were explored for the syntheses of amines, amides and heterocycles via dehydrogenation/rehydrogenation concept (commonly called as hydrogen borrowing process) under Cp*Ir III catalysis. [10] However,t he corresponding less expensive, air-stable, first group congener Cp*Co III [11] was not explored until now.I n continuation of our effort to develop sustainable chemistry under cobalt catalysis, [12] we lookedf or catalytic activities of novel Cp*Co III catalysts involving hydrogen transfer processes.…”

Rhodium(III)‐Catalyzed Synthesis of N‐(2‐Acetoxyalkyl)isoquinolones from Oxazolines and Alkynes through C−N Bond Formation and Ring‐Opening

“…More recently, some reports have appeared on the synthesis of N-alkyl-or -arylisoquinolone derivatives. [12][13][14] We focused on introducing the functional group at the Nalkyl chain of isoquinolone derivatives. With our ongoing interest in the synthesis of heterocycles, [15] herein, we report a rhodium(III)-catalyzed synthesis of N-(2-acetoxyalkyl)isoquinolones based on oxazoline-directed aromatic CÀH activation with alkynes.…”