Richter, FerdinandBirchall, NicholasFeil, Christoph M.Nieger, MartinGudat, Dietrich2024-09-272024-09-2720221420-30491905068484http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-149961http://elib.uni-stuttgart.de/handle/11682/14996http://dx.doi.org/10.18419/opus-14977The successful use of 1,3,4,2-triazaphospholenes (TAPs) as organo-catalysts stresses the need for efficient synthetic routes to these molecules. In this study, we establish the [1 + 4]-cycloaddition of PBr3 to azo-pyridines as a new approach to preparing pyrido-annellated TAPs in a single step from easily available precursors. The modular assembly of the azo-component via condensation of primary amines and nitroso compounds along with the feasibility of post-functionalization at the P-Br bond under conservation of the heterocyclic structure allows, in principle, to address a wide range of target molecules, which is illustrated by prototypical examples. The successful synthesis of a transition metal complex confirms for the first time the ability of a TAP to act as a P-donor ligand. Crystallographic studies suggest that hyperconjugation effects and intermolecular interactions induce a qualitatively similar ionic polarization of the P-Br bonds in TAPs as in better known isoelectronic diazaphospholenes.eninfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/4.0/540article2023-11-14