title: Gold-Catalyzed Regio- and Stereoselective   Acyloxyalkynylations and Cycloadditions of Alkynes
creator: Liu, Yaowen
subject: ddc-540
subject: 540 Chemistry and allied sciences
description: In Chapter 2, multi-substituted alkenes are accessible by a gold-catalyzed   acyloxyalkynylation of ynamides with ethynylbenziodoxolones (EBXs) in an   atom-economic fashion. The EBX reagents act as bifunctional reactants providing both the nucleophilic carboxylate as well as the alkynyl entity. Overall this cascade involves the formation of an alkynyl Au(III) species, stereoselective C(sp)-C(sp2) bond formation and C-O coupling at the alkynyl position of the ynamides. The introduced method features mild conditions and wide substrate scope. A number of tetrasubstituted amide enol 2-iodobenzoates bearing diverse functionalities were prepared in good to excellent yield. DFT calculations exlain the observed regioselectivity. The synthetic potential of the sequence was further documented by a number of selected follow-up transformations.  In Chapter 3, Tetrasubstituted alkenes including the ester and ether group, is of great interest in chemistry and material sciences. A variety of tetrasubstituted enol ether 2-iodobenzoate derivatives were prepared in good yields at room temperature through a gold-catalyzed acyloxyalkynylation of ynol ethers with ethynylbenziodoxolones (EBXs), which act as bifunctional reactants in an atom-economic fashion.   Furthermore, the mechanism involves an in situ formed alkynyl Au(III) species and a gram-scale reaction was efficiently conducted.  In Chapter 4, an efficient method for the construction of highly functionalized new spirooxindolocarbamates from a gold-catalyzed cycloaddition reaction of terminal alkyne and ynamides with isatin-derived ketimines is described. This protocol features easily accessible starting materials and good functional group compatibility enabling the introduction of various functionalized alkyne groups into cyclic carbamates. Gram-scale synthesis and proposed mechanism are also presented.
date: 2023
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/32582/1/Doctoral%20Thesis_Yaowen%20Liu_.pdf
identifier: DOI:10.11588/heidok.00032582
identifier: urn:nbn:de:bsz:16-heidok-325825
identifier:   Liu, Yaowen  (2023) Gold-Catalyzed Regio- and Stereoselective Acyloxyalkynylations and Cycloadditions of Alkynes.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/32582/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng