N-Tosylhydrazine-mediated deoxygenative hydrogenation of aldehydes and ketones catalyzed by Pd/C
摘要:
A mild and efficient method for the deoxygenative hydrogenation of aldehydes and ketones has been developed. The reaction is mediated by N-tosylhydrazine with H-2 (1 atm) as the reductant and 10% Pd/C as the catalyst. (C) 2013 Elsevier Ltd. All rights reserved.
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.
A formal [4 + 2] cycloaddition of N-tosylhydrazones with ortho-quinone methides was developed, affording the facile synthesis of diverse 1,3-oxazine derivatives under mild conditions. In this transformation, N-tosylhydrazones are used as a 1,2-dipole synthon under base-free conditions. Moreover, the substrate scope is broad, and the products are formed with high diastereoselectivities in most of the
coupling partners can be employed for the synthesis of conjugated dienes by palladium-catalyzed cross-coupling with tosylhydrazones: α,β-unsaturated ketone and aryl halide or alkenyl halide and non-conjugated tosylhydrazone. Depending on the substrate, a vinylogous hydride elimination is responsible for the formation of the final dienes.
Copper(I)-Catalyzed Alkylation of Polyfluoroarenes through Direct CH Bond Functionalization
作者:Shuai Xu、Guojiao Wu、Fei Ye、Xi Wang、Huan Li、Xia Zhao、Yan Zhang、Jianbo Wang
DOI:10.1002/anie.201412450
日期:2015.4.7
The copper(I)‐catalyzed alkylation of electron‐deficient polyfluoroarenes with N‐tosylhydrazones and diazo compounds has been developed. This reaction uses readily available starting materials and is operationally simple, thus representing a practical method for the construction of C(sp2)C(sp3) bonds with polyfluoroarenesthroughdirectCHbondfunctionalization. Mechanistically, copper(I) carbene
Wittig Ylide Mediated Decomposition of <i>N</i>-Sulfonylhydrazones to Sulfinates
作者:Deepika Choudhary、Vineeta Khatri、Ashok K. Basak
DOI:10.1021/acs.orglett.7b03953
日期:2018.4.6
N-Sulfonylhydrazones generate sulfinates selectively when treated with a stabilized Wittig ylide in a polar aprotic solvent at elevated temperature. The transition metal and base free decomposition method is applicable to N-sulfonylhydrazones generated from a number of aromatic and heteroaromatic aldehydes and ketones. In the case of N-tosylhydrazones derived from O-allyl and O-propargyl salicylaldehydes