Tetrahydrofuran (50 mL) and 4 angstrom molecular sieves (ca. 15 mL) were added to tert-butyl 2-(6-formylpyridin-2-yl)benzyl(phenyl)carbamate (11) (03.63 g, 9.34 mmol). Then 2,6-diisopropylaniline (1.66 g, 9.34 mmol) was added followed by a catalytic amount of p-toluenesulfonic acid monohydrate (0.003 g, 0.015 mmol). The mixture was stirred overnight then filtered and evaporated to a thick yellow oil. After several days the oil began to crystallize. Methanol (40 mL) was added and the mixture was stirred to give a yellow crystalline solid. The mixture was cooled to 5° C. for a couple of hours then the solid was collected on a glass fit and dried under reduced pressure. Yield: 3.93 g, 76.8%. 1H NMR (CD2Cl2, 500 MHz): 8.26 (s, 1H), 8.19 (d, 1H), 7.87 (t, 1H), 7.54 (d, 1H), 7.32-7.42 (m, 4H), 7.02-7.20 (m, 8H), 5.11 (s, 2H), 2.99 (sept, 2H), 1.34 (s, 9H), 1.18 (d, 12H).
