Reduction of Aldehydes and Ketones by Transition Metal Hydrides. Part 2. Reaction of trans , trans ‐[WH(CO) 2 (NO)(PMe 3 ) 2 ] with pyridine, functionalized aldehydes, and ketones

The reaction of trans , trans ‐[WH(CO) 2 (NO)(PMe 3 ) 2 ] ( 1 ) with (pyridin‐2‐yl)‐substituted aldehydes and ketones, (pyridin‐2‐yl)C(O)R where R = H, Me, Ph, pyridin‐2‐yl, and with 6‐methylpyridine‐2‐carbaldehyde was studied. In all cases, facile insertion of the CO bond into the WH bond was observed, with rapid subsequent extrusionof a coordinated CO ligand affording O , N ‐bidentate coordinated tungsten alkoxides. Only in case of pyridine‐2‐carbaldehyde and di(pyridin‐2‐yl) ketone, the initial n 1 O‐bonded insertion product could be observed as unstable intemediates by low‐temperature NMR.