Theoretical exploration of the radical and polar organometallic reactivity of Zn(SiR3)2 compounds towards alkynes
Frédéric Guégan
Laboratoire de Chimie Théorique, Université Pierre et Marie Curie, Paris, France
Mercredi 28 Mars 2018, 11h00
bibliothèque LCT, tour 12 - 13, 4ème étage
Recently the group of A. Pérez-Luna (IPCM) proposed a new synthetic approach to access substituted alkenes, based on the versatile reactivity of disilylzinc compounds towards alkynes. They could show that, depending on the nature of the silyl ligand, syn or anti silylzincation took place with good yields and selectivities, for a large range of R substituting groups.
Figure. Reactions under study.
In this presentation, I will show you some of the results we obtained in the theoretical investigation of this peculiar selectivity. Two principal mechanistic paths were investigated, one involving a "classical" polar addition of the disilylzinc moiety to the alkyne, and the second involving radical species.
As we will see, both mechanisms seem likely to occur, though reproduction of the experimental results (noticeably in terms of regioselectivity) is a rather tricky task. Through a progressive refinement of the theoretical models, further information can be gained on the physical roots of the observed selectivities, noticeably concerning the influence of the silyl and R substituting groups.
_________________________________
A few references on related works & experimental data:
[1] C. Fopp, E. Romain, K. Isaac, F. Chemla, F. Ferreira, O. Jackowski, M. Oestreich, and A. Pérez-Luna Org. Lett. 2016, 18, 2054.
[2] M. Yonehara, S. Nakamura, A. Murakana, and M. Uchiyama Chem. Asian J. 2010, 5/i>, 452.
[3] A. Pérez-Luna, C. Botuha, F. Ferreira, and F. Chemla Chem. Eur. J. 2008, 14, 8784.
[4] C. Chatgilialoglu Chem. Eur. J. 2008, 14, 2310.