The synthesis of 2-substituted oxazoles is achieved via nickel-catalyzed cross-coupling reaction of 2-methylthio-oxazole and various organozinc reagents. An extension of this method is demonstrated with a chemoselective, one-pot synthesis of unsymmetrical 2,5-disubstituted oxazoles. This synthesis of 2- and 2,5-substituted oxazoles using this method provides great advantages over previous methods for these compounds and is highly complementary to current cyclodehydration strategies.

The synthesis of 1H-indazoles is achieved from o-aminobenzoximes by the selective activation of the oxime in the presence of the amino group. The reaction occurs with a variety of substituted o-aminobenzoximes using a slight excess of methanesulfonyl chloride and triethylamine at 0-23 degrees C and is amenable to scale-up. The synthesis of 1H-indazoles under these conditions is extremely mild compared with previous synthetic approaches and affords the desired compounds in good to excellent yields.

The rapid synthesis of 2,4-and 2,5-disubstituted oxazoles via metal-catalyzed cross-coupling reactions is reported. The 4-or 5-position of the corresponding 4-or 5-halogenated 2-butylthiooxazoles was successfully functionalized via SuzukiMiyaura, Sonogashira and Stille cross-coupling reactions. The 2-position of the 2-butylthiooxazoles obtained was further coupled to various organozinc reagents through palladium-or nickel-mediated cross-coupling reactions.

The preparation of an enantiomerically enriched beta-diketimine composed of isoquinoline and 2-aminonaphthalene (IAN amine) is described, thereby offering new opportunities in the synthesis of nonracemic beta-diketimine- and pyridine-based chiral catalysts.

2’‐Aminoacetophenone Hydroxylamine hydrochloride Triethylamine Methanesulfonyl chloride 3‐Methyl‐1 H ‐indazole ( E )‐1‐(2‐Aminophenyl)ethanone oxime

Synthesis of 2,4-and 2,5-Disubstituted Oxazoles via Metal-Catalyzed Cross--Coupling Reactions. -(COUNCELLER, C. M.; EICHMAN, C. C.; PROUST, N.; STAMBULI*, J. P.; Adv. Synth. Catal. 353 (2011) 1, 79-83, http://dx.doi.org/10.1002/adsc.201000668 ; Dep. Chem., Ohio State Univ., Columbus, OH 43210, USA; Eng.) -Nuesgen 21-122

Pyrazole derivatives R 0180A Practical, Metal-Free Synthesis of 1H-Indazoles. -Cyclization of o-aminobenzoximes (I) proceeds smoothly in the presence of MesCl-Et 3 N by selective activation of the oxime in the presence of an amino group to afford indazoles (II). Mild reaction conditions are applied and a variety of substituents at both the oxime and amine group is tolerated. -(COUNCELLER, C. M.; EICHMAN, C. C.; WRAY, B. C.; STAMBULI*, J. P.; Org. Lett. 10 (2008) 5, 1021-1023; Dep. Chem., Ohio State Univ., Columbus, OH 43210, USA; Eng.) -Mischke 32-118

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