Nucleophilic additions to deactivated 2-fluoropyridine derivatives

ORGN 737

Martin Pettersson, martin.pettersson@pfizer.com, Subas M. Sakya, Christopher W. am Ende, and Longfei Xie. CNS Chemistry, PGRD, Pfizer Inc, Eastern Point Road, Groton, CT 06340

During the course of a recent drug discovery program, we required an efficient synthesis of 2-benzyloxy pyridine derivatives. The initial route relied on an alkylation of a 2-hydroxy pyridine intermediate, which proceeded in good overall yield but gave a mixture of products resulting from O- and N-alkylation. To avoid the need for separation of regioisomers, an alternative strategy was examined that involved nucleophilic addition to various 2-fluoropyridine derivatives.  We found that additions of a variety of primary and secondary alcohols proceed in excellent yield under mild conditions (KOt-Bu, THF, 50 ˚C, 2-6 h) even when strongly electron donating groups are present on the 2-fluoropyridyl template. This approach would be well suited for rapid expansion of chemical space using parallel medicinal chemistry.