Preparation of 2<i>H</i>-spiro[benzo[<i>d</i>]isothiazole-3,3′-pyrazole]-1, 1-dioxide-2′(4′<i>H</i>)-carboxylates from dilithiated<i>C</i>(α),<i>N</i>-carboalkoxyhydrazones and methyl 2-(aminosulfonyl)benzoate
作者:Anna C. Dawsey、Chandra Potter、John D. Knight、Zachary C. Kennedy、Ellyn A. Smith、Amanda M. Acevedo-Jake、Andrew J. Puciaty、Clyde R. Metz、Charles F. Beam、William T. Pennington、Donald G. VanDerveer
DOI:10.1002/jhet.50
日期:2009.3
A variety of substituted spiro(benzoisothiazole-pyrazoles) have been prepared by the condensation of dilithiated C(α),N-carboalkoxyhydrazones with lithiated methyl 2-(aminosulfonyl)benzoate followed by the cyclization of intermediates with acetic anhydride, which also resulted in spiro N-acetylated products when carbomethoxyhydrazones or carboethoxyhydrazones were used, and spiro NH products when
Rhodium-Catalyzed Oxidative Cycloaddition of <i>N</i>
-<i>tert</i>
-Butoxycarbonylhydrazones with Alkynes for the Synthesis of Functionalized Pyrroles <i>via</i>
C(<i>sp</i>
<sup>3</sup>
)-H Bond Functionalization
作者:Chun-Ming Chan、Zhongyuan Zhou、Wing-Yiu Yu
DOI:10.1002/adsc.201600900
日期:2016.12.22
The reaction features a regioselective α‐imino alkyl C(sp3)−H bond functionalization resulting in selective formation of highlyfunctionalized NH‐free pyrroles. Our studies showed that utilizing the N‐tert‐butoxycarbonyl (N‐Boc) as the oxidizing directing group is critical for achieving the observed pyrrole formation versus the isoquinoline formation. To account for the pyrrole formation, we hypothesized
A C–H activation-based strategy has been developed for the synthesis of N-amino azaheterocycles. Rh(III)-catalyzed coupling of N-Boc hydrazones/N-Boc hydrazines with diazodiesters/diazoketoesters provides convenient access to synthetically and medicinally important compounds, N-amino isoquinolin-3-ones and N-amino indoles, by harnessing N-tert-butyloxycarbonyl (N-Boc) cleavage as an adaptable reactivity
Pd(ii)-catalyzed direct C–H acylation of N-Boc hydrazones with aldehydes: one-pot synthesis of 1,2-diacylbenzenes
作者:Satyasheel Sharma、Aejin Kim、Jihye Park、Mirim Kim、Jong Hwan Kwak、Young Hoon Jung、Jung Su Park、In Su Kim
DOI:10.1039/c3ob41644e
日期:——
A palladium(II)-catalyzed directacylation of acetophenone N-Boc hydrazones with aldehydes via C–H bond activation is described. This protocol provides direct access to a range of 1,2-diacylbenzenes, which are useful precursors to construct biologically interesting and pharmaceutically important compounds.
An asymmetrichydrogenation of hydrazones with a unique nickel catalyst has been developed for the synthesis of chiral hydrazines with up to 99 % yield and 99.4 : 0.6 er and a broad substrate scope. Deuterium labelling experiments indicated that the hydrazone substrates undergo imine-enamine tautomerization in the mixed solvents.