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Charge-Transfer Complexes for Amine Synthesis 10.17863/CAM.64486 Kohara, Keishi Gaunt, Matthew A method to generate α-amino radicals, via a photoinduced charge-transfer complex, is reported. A multicomponent radical fragmentation-cyclization reaction was developed, combining secondary amines, cyclopropyl carboxaldehydes and alkenes, to generate cyclopentyl methylamines. To initiate the fragmentation step, single-electron reduction of alkyliminium ions to α-amino radicals was achieved, using an aromatic thiol and visible light irradiation. Mechanistic and computational studies supported the formation of a transient, ion-pair charge-transfer complex between iminium and thiolate ions. DFT calculations indicated that irradiation of the complex with visible light could promote intra-complex electron transfer from the thiolate HOMO to the iminium LUMO. This method of α-amino radical formation was extended to acyclic aldehydes, by development of a radical reductive amination, using thiol as the single-electron reductant and hydrogen atom source. Subsequently, the chemoselective reductive amination of secondary amines over primary amines was attempted. Preliminary studies on a di-amine drug indicated that the radical reductive amination had high selectivity for primary aminothiazoles over secondary amines, contrasting with existing polar reductive amination techniques. University of Cambridge 2020-08-23 Thesis Doctoral eng https://www.repository.cam.ac.uk/handle/1810/317373 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/6d7e5d7c-adb5-44ae-a097-59a7af14b13c/download d46aa0eb269850234782c6f3119c14fe https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/36f0af7a-ee43-4512-986f-cf006ab351dd/download 353adac0d1ebdfd65ab16480263c3c87 https://www.rioxx.net/licenses/all-rights-reserved/ Organic Chemistry Synthetic Methodology Photochemistry Charge-Transfer Complexes Radical Chemistry