The thiourea catalyzed enantioselective Michael addition of 5H-oxazol-4-ones to 2-enoylpyridine N-oxides is described. Under mild conditions, a series of optically active pyridine N-oxides inlaid with oxazolone motif were obtained in high yields (62-99%) with excellent stereoselectivities (84-> 99% ee and > 20:1 dr). Notably, the method offers a direct synthetic approach to enantioenriched pyridine N-oxides featured by vicinal oxygencontaining tetrasubstituted stereocenters.

Abstract. Mi Fu's aesthetic view on cursive script is very clear, that is, simple and elegant. Simple and elegant precisely requires a kind of natural and drifting quality as ancient people. This has created his unique small cursive script which seems contradictory with his running script creation, but the fact is that this aesthetic promoted the maturity and subsequent development of his running script style. The aesthetic of simple and elegant has a great significance on being able to see massive ruins of ancient calligraphy today.

Vertical and horizontal strokes with imagery, the first calligraphic criterion since the end of the Han Dynasty, refers to the associative imagery from the combinational relations among calligraphic strokes. Its establishment benefited from the perfection of the cursive script and was then applied to all calligraphy fonts. The imagery, which is from a very wide range of sources, can describe all aspects of calligraphy. Meanwhile, it is also some kind of psychological needs.