Titanocene‐Catalyzed Radical Opening of N‐Acylated Aziridines

• Published in: Angewandte Chemie International Edition Vol. 56; no. 41; pp. 12654 - 12657
• Main Authors: Zhang, Yong‐Qiang, Vogelsang, Elisabeth, Qu, Zheng‐Wang, Grimme, Stefan, Gansäuer, Andreas
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 02.10.2017; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Acylation; aziridines; Catalysis; Chemistry; Chemistry, Multidisciplinary; conjugate addition; Electron transfer; Physical Sciences; radical ring opening; reduction; Ring opening; Science & Technology; titanocenes; aziridines; AUXILIARY BASIS-SETS; EPOXIDE; conjugate addition; radical ring opening; ELECTRON-TRANSFER; ZETA VALENCE QUALITY; titanocenes; ATOMS; AMINOKETYL RADICALS; reduction; AMIDE BOND; UMPOLUNG; CYCLIZATION
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201707673

Aziridines activated by N‐acylation are opened to the higher substituted radical through electron transfer from titanocene(III) complexes in a novel catalytic reaction. This reaction is applicable in conjugate additions, reductions, and cyclizations and suited for the construction of quaternary carbon centers. The concerted mechanism of the ring opening is indicated by DFT calculations. Useful intermediates for intermolecular additions, reductions, and cyclizations are obtained with excellent regioselectivity via β‐amido‐substituted radicals catalytically generated from N‐acyl aziridines. DFT calculations indicate that the ring opening is concerted rather than stepwise as previously postulated.