Synthesis and reactivity of 2-thionoester pyrroles: a route to 2-formyl pyrroles

Abstract

The one-step desulfurative reduction of 2-thionoester pyrroles provides 2-formyl pyrroles, including the opportunity to access the deuterated variant.

Recent Advances for the Synthesis of N‐Unsubstituted Pyrroles

“…Knorr‐type approach for the synthesis of o ‐ethyl 2‐thionoester pyrroles 135 a , e was described by Thompson et al (Scheme 45). [45] Further, Raney nickel was used for the reduction of the thionoester moiety to an aldehyde (Scheme 46). The developed alternative route to 2‐formyl pyrroles 136 eliminates the widely used additional hydrolysis/decarboxylation/formylation steps which are usually required for the conversion of Knorr‐type 2‐carboxylate pyrroles into 2‐formyl pyrroles.…”

“…Knorr-type approach for the synthesis of o-ethyl 2-thionoester pyrroles 135 a,e was described by Thompson et al (Scheme 45). [45] Further, Raney nickel was used for the reduction of the thionoester moiety to an aldehyde (Scheme 46). The…”