Directed C–C bond cleavage of a cyclopropane intermediate generated from<i>N</i>-tosylhydrazones and stable enaminones: expedient synthesis of functionalized 1,4-ketoaldehydes
-quaternary centers via regioseletive C-C bond activation has been described. Through cyclopropanation of bench-stable enaminones with in situ generated diazo reagents from N-tosylhydrazones, followed by selective C-C bond cleavage of the cyclopropane ring affords the 1, 4-ketoaldehyde derivatives in good to excellent yields. This method works with broad substrate scope and high regioseletivity.
Zinc-promoted cyclization of tosylhydrazones and 2-(dimethylamino)malononitrile: an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles
A Zn(OTf)2-promoted cyclization reaction of tosylhydrazones with 2-(dimethylamino)malononitrile has been successfully developed providing an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles.
I<sub>2</sub>–TBHP-Catalyzed Oxidative Cross-Coupling of <i>N</i>-Sulfonyl Hydrazones and Isocyanides to 5-Aminopyrazoles
作者:Gopal Chandru Senadi、Wan-Ping Hu、Ting-Yi Lu、Amol Milind Garkhedkar、Jaya Kishore Vandavasi、Jeh-Jeng Wang
DOI:10.1021/acs.orglett.5b00398
日期:2015.3.20
I-2-TBHP-catalyzed oxidative cross coupling of N-sulfonyl hydrazones with isocyanides has been realized for the synthesis of 5-aminopyrazoles through formal [4 + 1] annulation via in situ azoalkene formation. Notable features are the metal/alkyne-free strategy, C-C and C-N bond formation, atom economy, catalytic I-2, broad functional group tolerance, good reaction yields, shorter time, and also applicability to one-pot methodology.
Pd‐Catalyzed Tandem Coupling Reaction of 2‐
<i>gem</i>
‐Dibromovinylanilines and
<i>N</i>
‐Tosylhydrazones to Construct 2‐(1‐phenylvinyl)‐indoles
A novel palladium(0)‐catalyzed intermolecular coupling reaction of 2‐gem‐dibromovinylanilines and N‐tosylhydrazones was reported to construct 2‐(1‐phenylvinyl)‐indoles efficiently. The indole bearing 1, 1‐disubstituted alkenes were obtained in one step with short reaction time, in high yields and broad substrate scope. The formed indole derivates could be easily transformed into much more valuable