01609nas a2200193   4500008004100000022001400041245017600055210006900231260000800300300001600308490000700324520085300331100002001184700001801204700001601222700002401238700002201262856013101284       2022                        eng d  a2041-652000aDynamic kinetic resolution of gamma,gamma-disubstituted indole 2-carboxaldehydes via NHC-Lewis acid cooperative catalysis for the synthesis of tetracyclic epsilon-lactones0 aDynamic kinetic resolution of gammagammadisubstituted indole 2ca  cOCT  a11513-115180 v133 a<p>
	The ubiquity of epsilon-lactones in various biologically active compounds inspired the development of efficient and enantioselective routes to these target compounds. Described herein is the enantioselective synthesis of indole-fused epsilon-lactones by the N-heterocyclic carbene (NHC)-Lewis acid cooperative catalyzed dynamic kinetic resolution (DKR) of in situ generated gamma,gamma-disubstituted indole 2-carboxaldehydes. The Bi(OTf)(3)-catalyzed Friedel-Crafts reaction of indole-2-carboxaldehyde with 2-hydroxy phenyl p-quinone methides generates gamma,gamma-disubstituted indole 2-carboxaldehydes, which in the presence of NHC and Bi(OTf)(3) afforded the desired tetracyclic epsilon-lactones in up to 93% yield and &gt;99 : 1 er. Moreover, preliminary studies on the mechanism of this formal [4 + 3] annulation are also provided.</p>
1 aBalanna, Kuruva1 aBarik, Soumen1 aShee, Sayan1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/dynamic-kinetic-resolution-gammagamma-disubstituted-indole-2-carboxaldehydes-nhc-lewis-acid