C–H insertions in oxidative gold catalysis: synthesis of polycyclic 2H-pyran-3(6H)-ones via a relay strategy. Issue 12 (27th October 2015)

• Record Type: Journal Article
• Authors: Zheng, Zhitong; Zhang, Liming
• Is Part Of: Organic chemistry frontiers. Volume 2:Issue 12(2016:Dec.)
• Page Start: 1556
• Page End: 1560
• Publication Date: 2015-10-27
• Subjects: Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1039/c5qo00308c
• Languages: English
• ISSNs: 2052-4110

Abstract

Abstract : A new application of oxidatively generated, highly electrophilic α-oxo gold carbenes in synthetically streamlining insertions into unactivated C–H bonds is realized by converting them to putative vinyl cation intermediates in a relay approach. This chemistry permits expedient access to cyclic dihydropyran-3-ones. Abstract : An expedient synthesis of bicyclic/polycyclic 2 H -pyran-3(6 H )-ones is realized in a cascade cyclization triggered by oxidative gold catalysis and terminated by streamlining C–H insertions. In this reaction, an α-oxo gold carbene intermediate, initially formed upon gold-catalyzed oxidation of alkynes, could be trapped by a tethered C–C triple bond, thereby resulting in the formation of a putative vinyl cation intermediate. This intermediate of high electrophilicity is proposed to be responsible for intramolecular C–H insertions, the mostly concerted nature of which is established by the reactions of chiral substrates. The reaction provides a rapid approach to the construction of functionalized polycyclic systems from easily accessible bispropargyl ethers and with minimal structural prefunctionalization.