Ag-Catalyzed Oxidative ipso-Cyclization via Decarboxylative Acylation/Alkylation: Access to 3-Acyl/Alkyl-spiro[4.5]trienones

Abstract

A strategy to functionalized spiro[4.5]­trienones, by domino silver-catalyzed decarboxylative acylation or alkylation/ ipso-cyclization of N-arylpropiolamides with α-keto acids/alkyl carboxylic acids, is presented. This transformation offers a wide range of substituted 3-acyl/alkyl-spiro[4.5]­trienones in high yields with a broad substrate scope. The approach was further extended to access fused tricyclic frameworks, 6,7-dihydro-3H-pyrrolo­[2,1-j]­quinoline-3,9­(5H)-diones.

Cerium(IV)‐Mediated Carbon‐Carbon Bond Formation for the Synthesis of Spirodienone Lactams

“…Since these ynamido‐phosphonates have similarities with α‐AAPs, we studied their reactivity towards CAN oxidation reactions to overcome some of the limitations observed in the use of α‐AAPs and α‐AAPOs. Moreover, it has been reported in the literature that the formation of spirocyclic compounds may occur from electron‐poor alkynes for instance through the addition of a radical leading to the conclusion that ynamide‐phosphonates such as 34 may be of interest in the synthesis of spirocyclic compounds [35–41] …”

“…Moreover, it has been reported in the literature that the formation of spirocyclic compounds may occur from electron-poor alkynes for instance through the addition of a radical leading to the conclusion that ynamidephosphonates such as 34 may be of interest in the synthesis of spirocyclic compounds. [35][36][37][38][39][40][41] With the goal to prepare the spirodienone lactam 16 b (EWG = Ts) we next explored the reactivity of the ynamidophosphonates 34 [34] towards the oxidation with CAN in CH 3 CN. In that case, the oxidation of 34 led to the formation of the three products 35-37 resulting from the easier oxidation of the alkyne moiety in comparison to the PMB ring.…”

Alternative and Uncommon Acylating Agents – An Alive and Kicking Methodology

“…[13] Recently, Prajapti group reported the Ag-catalyzed decarboxylative acylation of Narylpropiolamides 18 with pyruvic acid 19 via ipso-cyclization leads to biologically relevant 3-acyl-spiro[4.5]trienones 20 (Scheme 2). [14]…”

Visible‐light‐mediated Synthesis of Bromo‐containing Azaspirotrienediones from N‐phenylpropynamides

“…Therefore, the synthesis of spirocyclohexadienones has received great attention [3a–c] . The synthetic methods mainly adopt the strategy of dearomatization reactions.– [3d–7] For example, various substituted azaspirotrienediones, an important class of spirocyclohexanediones, can be obtained by dearomatization of N ‐arylpropiolamides or N ‐( p ‐methoxyaryl) propionamides through radical addition/ ipso ‐cyclization/oxidation cascade reaction using transition metal (copper, [4a–c] iron [4d] or silver [4e,f] ) catalysis in the presence of oxidants (eqn (a), Scheme 1). In addition, azaspirotrienediones can also be achieved by the dearomatization of N ‐arylpropionamides or N ‐( p ‐methoxyaryl) propionamides under transition metal‐free conditions by using excessive oxidants such as K 2 S 2 O 8 [7a] or t BuOOH [7b] at elevated temperatures (eqn (b), Scheme 1).…”