Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 7, 2020
Previous Article Next Article

Dual reactivity of B(C6F5)3 enables the silylative cascade conversion of N-aryl piperidines to sila-N-heterocycles: DFT calculations

Author affiliations

Abstract

The first catalytic access to bridged sila-N-heterocycles from piperidines via cascade sp3 and sp2 C–Si bond formation all mediated by a single catalyst B(C6F5)3 (A) has been recently developed by Park and Chang. Described herein is a theoretical study of the B(C6F5)3-catalyzed silylative cascade conversion of N-aryl piperidines (H) to afford polycyclic azasilaheterocycles with a strong emphasis on the dual reactivity of B(C6F5)3. The DFT calculations show that the catalyzed reaction involves three steps of the cascade reaction: (i) the formation of tetrahydropyridine (I) upon dehydrogenation of the piperidine; (ii) β-selective hydrosilylation of tetrahydropyridine; (iii) an intramolecular sila-Friedel–Crafts reaction to form a bridged sp2 C–Si bond. The N-silyl piperidinium borohydride (A′) turns out to be the thermodynamically favored, resting species of the overall reaction, which is consistent with the observation of a species such as A′ during borane catalysis. The DFT calculations suggest that the β-selective hydrosilylation of I is the rate-determining step in the entire catalytic cycle, while the liberated I reacts with B(C6F5)3 to form a zwitterion consisting of iminium and borate units (O). The calculated sila-Friedel–Crafts reactions of a range of presupposed silylated (cyclic)aza intermediates imply the importance of structural integrity on the piperidinyl unit of substrates.

Graphical abstract: Dual reactivity of B(C6F5)3 enables the silylative cascade conversion of N-aryl piperidines to sila-N-heterocycles: DFT calculations

Back to tab navigation

Supplementary files

Article information


Submitted
01 Dec 2019
Accepted
26 Feb 2020
First published
27 Feb 2020

Org. Chem. Front., 2020,7, 944-952
Article type
Research Article

Dual reactivity of B(C6F5)3 enables the silylative cascade conversion of N-aryl piperidines to sila-N-heterocycles: DFT calculations

M. Zhou, S. Park and L. Dang, Org. Chem. Front., 2020, 7, 944
DOI: 10.1039/C9QO01437C

Social activity

Search articles by author

Spotlight

Advertisements