Chemo- and Regioselective Alkylation of Pyridine N-Oxides with Titanacyclopropanes
Li-Chen Xu1, Xiao-Di Ma1, Kun-Ming Liu1
1College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China.
Abstract:
While titanacyclopropanes are used to react mainly with ester, amide, and cyano to undergo cyclopropanation, herein they react preferentially with pyridine N-oxide to accomplish C2-H alkylation beyond these functionalities with double regioselectivity. After being pyridylated at the less hindered C-Ti bond, the remaining C-Ti bond of titanacyclopropanes can be further functionalized by various electrophiles, allowing facile introduction of complex alkyls onto the C2 of pyridines. Its synthetic potential has been demonstrated by late-stage diversification of drugs.
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