Direct Cα-heteroarylation of structurally diverse ethers via a mild N-hydroxysuccinimide mediated cross-dehydrogenative coupling reaction

Abstract

A new, efficient, N-hydroxysuccinimide (NHS) mediated, mild and metal-free CDC strategy for the direct Cα-heteroarylation of diverse ethers has been developed.

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

“…[60] Thedirect alkylation of nonfunctionalized pyridines and related azines could also be promoted with cyclic and acyclice thers (as well as with some cyclic alkanes) by using K 2 S 2 O 8 as an oxidant. [65] Thetransient aoxygenated radical intermediates involved in these processes can also be generated by photoredox catalysis,a sn icely exploited by MacMillan to promote the alkylation of isoquinoline and some other nitrogen-containing heterocycles with cyclic as well as some acyclic ethers in good yields. [64] Ac ombination of (NH 4 ) 2 S 2 O 8 and N-hydroxysuccinimide was also shown to promote the cross-dehydrogenative coupling between cyclic ethers and N-heteroarenes in good yields.…”

“…[64] Ac ombination of (NH 4 ) 2 S 2 O 8 and N-hydroxysuccinimide was also shown to promote the cross-dehydrogenative coupling between cyclic ethers and N-heteroarenes in good yields. [65] Thetransient aoxygenated radical intermediates involved in these processes can also be generated by photoredox catalysis,a sn icely exploited by MacMillan to promote the alkylation of isoquinoline and some other nitrogen-containing heterocycles with cyclic as well as some acyclic ethers in good yields. [66] Photoredox catalysis using tetrabutylammonium decatungstate as ap hotoredox catalyst was also exploited by Ravelli, Ryu, and co-workers to promote such kinds of crossdehydrogenative coupling reactions.…”

Beyond Friedel and Crafts: Innate Alkylation of C−H Bonds in Arenes

“…The same oxidant could also be used to promote the direct alkylation of pyridine N ‐oxides with cyclic ethers by using copper(II) oxide as a catalyst . A combination of (NH 4 ) 2 S 2 O 8 and N ‐hydroxysuccinimide was also shown to promote the cross‐dehydrogenative coupling between cyclic ethers and N‐heteroarenes in good yields . The transient α‐oxygenated radical intermediates involved in these processes can also be generated by photoredox catalysis, as nicely exploited by MacMillan to promote the alkylation of isoquinoline and some other nitrogen‐containing heterocycles with cyclic as well as some acyclic ethers in good yields .…”

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

“…[64] Eine Kombination aus (NH 4 ) 2 S 2 O 8 und N-Hydroxysuccinimid fçrderte in guten Ausbeuten die dehydrierende Kreuzkupplung zwischen cyclischen Ethern und N-Heteroarenen. [65] Die an diesen Prozessen beteiligten transienten a-oxygenierten Radikalintermediate kçnnen auch photoredoxkatalytisch erzeugt werden, was von MacMillan zur Fçrderung der Alkylierung von Isochinolinen und weiteren stickstoffhaltigen Heterocyclen mit cyclischen und mehreren acyclischen Ethern in guten Ausbeuten genutzt wurde. [66] Die Photoredoxkatalyse wurde außerdem von Ravelli und Ryu fürs olche dehydrierende Kreuzkupplungen mit Te trabutylammoniumdecawolframat als Photoredoxkatalysator ausgenutzt.…”