A gold-catalyzed cyclization of conjugated ynones with various nucleophiles such as indoles, alcohols, and thiols has been developed. The reaction provides a new and efficient protocol for the synthesis of functionalized pyrroles with wide versatility and functional group compatibility. Remarkably, for indolyl, alkoxy, or sulfenyl pyrroles, all could be constructed efficiently by this single methodology. In addition, cis-hydrofunctionalizations of ynones are involved in these reactions.

A new and efficient method for the synthesis of unsymmetrical 1,3‐butadiynes by gold‐catalyzed C(sp)–C(sp) cross‐coupling of terminal alkynes with alkynyl hypervalent iodine(III) reagents has been developed. The reaction features high selectivity and efficiency, mild reaction conditions, wide substrate scope, and functional‐group compatibility, and is a highly attractive complement to existing methods. Mechanistic studies reveal that formation of a phenanthrolinyl‐ligated gold(I) complex is crucial for the efficiency and selectivity of the target transformation.

A straightforward synthesis of pyrimidines via Au(III) or Au(I)/Lewis-acid-catalyzed cascade reactions of propargyl alcohols with 3-amino-benzo[d]isoxazoles is described. The propargyl amine intermediates are readily generated in situ via oxophilic activation of gold(III) or a Lewis acid, which undergo cyclization/1,2-group migration/aromatization to deliver the desired products. Highly selective 1,2-H or -R 1 migrations are observed in most cases, and the migratory aptitude is dependent on the steric and electronic properties of the propargylic groups.In conclusion, we have disclosed that Au(III) or Au(I) complex/Lewis acid could efficiently catalyze a cascade substitution/cyclization/1,2-group migration reaction of propargyl alcohols with 3-amino-benzo [d]isoxazoles. The reaction provides a facile method for the synthesis of pyrimidine derivatives. Highly selective 1,2-H or -R 1 migrations were observed in most cases, and the migratory aptitude is dependent on the steric and electronic properties of the groups at the propargylic position. Further works on synthetic applications are in progress in our laboratory. ■ ASSOCIATED CONTENT* sı Supporting InformationThe Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.orglett.2c01011. Experimental details and spectroscopic characterization of all new compounds, (PDF)Accession Codes CCDC 2126735−2126738, 2151398, and 2158901 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk