title: Pd-Catalyzed, Ligand-Enabled Stereoselective 1,2-Iodine(III) Shift/1,1-Carboxyalkynylation of Alkynylbenziodoxoles.
abstract: A PdII-catalyzed 2:1 coupling reaction of alkynylbenziodoxole with carboxylic acid to afford (alk-1-en-3-ynyl)benziodoxole, which is efficiently promoted by an octahydrophenazine ligand, is reported. The reaction involves a Pd-assisted 1,2-iodine(III) shift of the alkynylbenziodoxole followed by stereoselective introduction of carboxy and alkynyl groups (the latter originating from another molecule of the alkynylbenziodoxole) into the 1-position of the transient Pd-vinylidene species. The product of this 1,1-carboxyalkynylation reaction serves as a new functionalized enyne-type building block for further synthetic transformations.
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
authors.forename: Junliang
authors.initials: J
authors.lastname: Wu
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
authors.forename: Hajime
authors.initials: H
authors.lastname: Hirao
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
authors.forename: Naohiko
authors.identifier: http://orcid.org/0000-0002-8997-3268
authors.initials: N
authors.lastname: Yoshikai
keywords: alkynylation; carboxylic acid; cross-coupling; hypervalent iodine; palladium