Chen Z, Li YF, Tan SZ, Ouyang Q, Chen ZC, Du W, Chen YC. Formal nucleophilic pyrrolylmethylation
via palladium-based auto-tandem catalysis: switchable regiodivergent synthesis and remote chirality transfer.
Chem Sci 2022;
13:12433-12439. [PMID:
36349271 PMCID:
PMC9628985 DOI:
10.1039/d2sc05210e]
[Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 10/05/2022] [Indexed: 09/10/2023] Open
Abstract
Although nucleophilic benzylation-type reaction to introduce various aromatic systems into molecules has been widely explored, the related pyrrolylmethylation version remains to be disclosed. Reported herein is a palladium-catalysed multiple auto-tandem reaction between N-Ts propargylamines, allyl carbonates and aldimines in the presence of an acid, proceeding through sequential allylic amination, cycloisomerisation, vinylogous addition and aromatisation steps. A diversity of formal pyrrolylmethylated amine products were finally furnished efficiently. In addition, switchable regiodivergent 3-pyrrolylmethylation and 4-pyrrolylmethylation were realised by tuning catalytic conditions. Moreover, remote chirality transfer with readily available enantioenriched starting materials was well achieved with an achiral ligand, relying on diastereoselective generation of η2-Pd(0) complexes between Pd(0) and chiral 1,3-diene intermediates in the key vinylogous addition step. A few control experiments were conducted to elucidate the palladium-involved tandem reaction and regiodivergent synthesis.
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