Abstract
Positively charged molecules and intermediates exhibit unique reactivity and properties. In this context, studies on helical cationic edifices will be presented. These compounds exhibit novel chemical and electronic properties thanks to the extended delocalization provided by the triarylcarbenium backbone. 1] Molecular engineering aimed at obtaining new reactivities and properties, electronic and chiroptical in particular, will be presented. 2]
Emphasis will also be placed on metal-catalyzed decompositions of a-diazocarbonyl compounds.[3] Particular attention will be paid to routes to ylide intermediates, followed by functionally rich heterocyclic derivatives. Research into new tetrahetero-functionalized methanes, i.e. with substituted tetraoxa and azatrioxa carbon atoms, exhibiting remarkable enantiomerization barriers with values of up to 34.6 kcal/mol (half-lives >84'000 years at 25 °C), will be detailed ; the link with the chemistry of intermediate carbocations will be made during the lecture.
References
[1] J. Bosson, N. Bisballe, B. W. Laursen, J. Lacour, in Helicenes. Synthesis, Properties and Applications (Eds.: J. Crassous, I. G. Stara, I. Stary), Wiley-VCH, 2022, pp. 127-165.
[2] a) B. Fabri, D. F. De Rosa, D. J. Black, R. Mucci, A. Krimovs, R. Pal, J. Lacour, Chem. Eur. J. 2025, 31, e202501212; b) S. G. Stenspil, A. H. Olsson, R. Mucci, M. Pink, C. Besnard, G. Pescitelli, J. Lacour, A. H. Flood, B. W. Laursen, Angew .Chem. Int. Ed. 2024, e202412320; c) B. Fabri, T. Funaioli, L. Frédéric, C. Elsner, E. Bordignon, F. Zinna, L. Di Bari, G. Pescitelli, J. Lacour, J. Am. Chem. Soc. 2024, 146, 8308-8319; d) R. Tarrieu, I. Hernández Delgado, F. Zinna, V. Dorcet, S. Colombel-Rouen, C. Crévisy, O. Baslé, J. Bosson, J. Lacour, Chem. Commun. 2021, 75, 3793-3796; e) J. Bosson, G. M. Labrador, C. Besnard, D. Jacquemin, J. Lacour, Angew. Chem. Int. Ed. 2021, 60, 8733-8738; f) H. Li, R. Duwald, S. Pascal, S. Voci, C. Besnard, J. Bosson, L. Bouffier, J. Lacour, N. Sojic, Chem. Commun. 2020, 56, 9771-9774; g) R. Duwald, J. Bosson, S. Pascal, S. Grass, F. Zinna, C. Besnard, L. Di Bari, D. Jacquemin, J. Lacour, Chem. Sci. 2020, 11, 1165-1169.
[3] a) O. Viudes, C. Besnard, A. F. Siegle, O. Trapp, T. Bürgi, G. Pescitelli, J. Lacour, J. Am. Chem. Soc. 2025, 147, 21121-21130; b) C. Montagnon, J. R. Bultel, C. Besnard, L. Guénée, J. Lacour, Chem. Eur. J. 2024, e202401522; c) Y. Nikolova, B. Fabri, P. Moneva Lorente, A. Guarnieri-Ibáñez, A. de Aguirre, Y. Soda, G. Pescitelli, F. Zinna, C. Besnard, L. Guénée, D. Moreau, L. Di Bari, E. Bakker, A. I. Poblador-Bahamonde, J. Lacour, Angew. Chem. Int. Ed. 2022, 61, e202210798; d) J. Viñas-Lóbez, G. Levitre, A. De Aguirre, C. Besnard, A. I. Poblador-Bahamonde, J. Lacour, ACS Org. Inorg. Au 2021, 1, 11-17; e) T. Achard, C. Tortoreto, A. I. Poblador-Bahamonde, L. Guénée, T. Bürgi, J. Lacour, Angew. Chem. Int. Ed. 2014, 53, 6140-6144; f) C. Tortoreto, T. Achard, W. Zeghida, M. Austeri, L. Guénée, J. Lacour, Angew. Chem. Int. Ed. 2012, 51, 5847-5851.
