Cu‐TEMPO Catalyzed Dehydrogenative Friedlander Annulation/sp³ C–H Functionalization/Spiroannulation towards Spiro[indoline‐3,3'‐pyrrolizin]‐2'‐yl)‐4‐phenylquinoline‐3‐Carboxylates

Abstract

A series of spiro[indoline‐3,3'‐pyrrolizin]‐2'‐yl)‐4‐phenylquinoline‐3‐carboxylate 6 from 2‐amino‐5‐chlorobenzhydrol 1, benzyl alcohols 3, and methyl or ethyl acetoacetate 2 is reported by the Cu(OAc)2, TEMPO catalyzed dehydrogenative Friedlander annulation/sp3–CH‐functionalization/regioselective 1,3‐ dipolar cyclo‐ addition. Likewise, chimanine A analogues 7 were obtained using a similar strategy in DES (Deep Eutectic Solvents) as a reaction medium in excellent yields.

Decarboxylative 1,3-dipolar cycloadditions of l-proline

“…In another report by the Khan team, they again employed Cu(OAc) 2 /TEMPO as an efficient catalytic system for the dehydrogenative Friedlander annulation of secondary alcohols, followed by C(sp 3 )-H functionalization by primary alcohols, and subsequent regioselective 1,3-DC with azomethine ylids ( Scheme 35 ). 81 Considering the mechanism in Scheme 36 , from the interaction of active TEMPO with Cu( ii ) ions, TEMPOH and Cu( i ) species were generated, which transferred an electron to 121. Ketone A which formed through this process, reacted with alkyl acetoacetate 123 to produce methyl quinoline B after the dehydration in a deep eutectic solvent (DES).…”

Deep Eutectic Solvents as à-la-Carte Medium for Transition-Metal-Catalyzed Organic Processes

“…A similar approach was also applied in the mixture DMU:tartaric acid (7:3) in the presence of an iridium catalyst to access (E)-4-benzylidenylacridines and (E)-2-styrilquinoline-3-carboxamides [ 87 ]. To further expand this strategy, the same authors also synthesized a series of spiro[indoline-3,3′-pyrrolizin]-2′-yl)-4-phenylquinoline-3-carboxylates, in this case performing the C(sp 3 )-H functionalization using Cu(OAc) 2 and TEMPO as a catalytic system ( Figure 30 , Table 4 , entry 3) [ 88 ].…”

Mn-Catalyzed Ligand-Free One-Pot Synthesis of (E)-6,7-Dihydrodibenzo[b,j][1,7]phenanthrolines and (E)-1,2,3,4-Tetrahydrobenzo[b][1,6]naphthyridines through Dehydrogenative Friedlander Annulation/C(sp3)–H Functionalization

“…38−42 DES has several advantages, including nontoxicity, biodegradability, low cost, easy synthesis, and good thermal stability; it acts as a catalyst as well as a solvent. 43,44 This article is licensed under CC-BY-NC-ND Our research team has recently focused on deep eutectic solvents, for example, Ir-, 45 Cu-, 46 and Ru-catalyzed 47 synthesis of quinolones, dehydrogenative Friedlander annulation, and C(sp 3 )−H functionalizations. In our continued research, Mncatalyzed dehydrogenative Friedlander annulation/alkenylation or C(sp 3 )−H functionalization is reported here in this article.…”

“…Our research team has recently focused on deep eutectic solvents, for example, Ir-, 45 Cu-, 46 and Ru-catalyzed 47 synthesis of quinolones, dehydrogenative Friedlander annulation, and C(sp 3 )–H functionalizations. In our continued research, Mn-catalyzed dehydrogenative Friedlander annulation/alkenylation or C(sp 3 )–H functionalization is reported here in this article.…”