Singh C, Prakasham AP, Gangwar MK, Butcher RJ, Ghosh P. One-Pot Tandem Hiyama Alkynylation/Cyclizations by Palladium(II) Acyclic Diaminocarbene (ADC) Complexes Yielding Biologically Relevant Benzofuran Scaffolds.
ACS OMEGA 2018;
3:1740-1756. [PMID:
31458491 PMCID:
PMC6641338 DOI:
10.1021/acsomega.7b01974]
[Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/23/2018] [Indexed: 06/10/2023]
Abstract
A series of palladium acyclic diaminocarbene (ADC) complexes of the type cis-[(R1NH)(R2)methylidene]PdCl2(CNR1) [R1 = 2,4,6-(CH3)3C6H2: R2 = NC5H10 (2); NC4H8 (3); NC4H8O (4)] were used not only to perform the Csp2 -Csp Hiyama coupling between aryl iodide and triethoxysilylalkynes but also to subsequently carry out the one-pot tandem Hiyama alkynylation/cyclization reaction between 2-iodophenol and triethoxysilylalkynes, giving a convenient time-efficient access to the biologically relevant benzofuran compounds. The palladium ADC complexes (2-4) were conveniently synthesized by the nucleophilic addition of secondary amines, namely, piperidine, pyrrolidine, and morpholine on the cis-{(2,4,6-(CH3)3C6H2)NC}2PdCl2 in moderate yields (ca. 61-66%).
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