Removal of the pyridine directing group from $\alpha$-substituted N-(pyridin-2-yl)piperidines obtained via directed Ru-catalyzed $sp^{3}$ C-H functionalization

Two strategies, hydrogenationhydride reduction and quaternizationhydride reduction, are reported that make use of mild reaction conditions (room temperature) to efficiently remove the N-pyridin-2-yl directing group from a diverse set of C-2-substituted piperidines that were synthesized through directed Ru-catalyzed sp3 CH functionalization. The deprotected products are obtained in moderate to good overall yields irrespective of the strategy followed, indicating that both methods are generally equally effective. Only in the case of 2,6-disubstituted piperidines, could the quaternizationhydride reduction strategy not be used. The hydrogenationhydride reduction protocol was successfully applied to trans- and cis-2-methyl-N-(pyridin-2-yl)-6-undecylpiperidine in a short synthetic route toward (±)-solenopsin A (trans diastereoisomer) and (±)-isosolenopsin A (cis diastereoisomer). The absolute configuration of the enantiomers of these fire ant alkaloids could be determined via VCD spectroscopy.

Jaar van publicatie:2013

Trefwoorden:A1 Journal article

BOF-keylabel:ja

BOF-publication weight:3

CSS-citation score:2

Authors from:Higher Education

Toegankelijkheid:Closed