All products obtained in collidine experiments (product 6) from Table I were fully characterized using 1 H and 13 C NMR, IR, and C, H analysis. 1 H NMR spectra for these amides show two singlets for each set of protons corresponding to two different rotamers (≈1:1). A variable temperature 1 H NMR experiment revealed that the rotamers undergo coalescence at ≈70°C. (b) Product 6 (entry c) was treated with tetrabutylammonium fluoride and the reduced amide (product ...