Practical Approach for Preparation of Unsymmetric Benzils from β-Ketoaldehydes

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 http://pubs.acs.org/doi/abs/10.1021/ol403762e

Practical Approach for Preparation of Unsymmetric Benzils from β-Ketoaldehydes

Libo Ruan, Min Shi, Nian Li, Xu Ding, Fan Yang, and Jie Tang

pp 733–735

Publication Date (Web): January 29, 2014 (Letter)

DOI: 10.1021/ol403762e

 

 An efficient and practical method for the synthesis of unsymmetric benzils from readily available β-ketoaldehydes has been developed. Various unsymmetric 1,2-diaryldiketones bearing functional groups have been obtained in good to excellent yields under mild reaction conditions. A plausible mechanism was proposed, and α,α-dichloroketone was considered as the key intermediate. The generation of α,α-dichloroketones from β-ketoaldehydes may undergo the following steps: (1) oxidation by sodium hypochlorite, (2) decarboxylation, and (3) chlorination by Cl₂ generated from sodium hypochlorite.

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Organic Synthesis: The Disconnection Approach

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Buckyball boron

The stability of the predicted boron cage stems from its unique structural geometry
 Since C₆₀ fullerene’s discovery in 1985 and the subsequent Nobel prize awarded to Robert Curl, Harry Kroto and Richard Smalley in 1996, researchers have been challenging themselves to make similar structures with other elements in the hope of finding exciting alternative nano building blocks.
 http://www.rsc.org/chemistryworld/2014/07/boron-cage-b38-fullerene

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Hydrophobic Catalysts

Hydrophobic Catalysts

Tetrahedron. Author manuscript; available in PMC Feb 4, 2013.

Published in final edited form as:

Tetrahedron. Feb 4, 2012; 68(5): 1359–1366.

Published online Dec 13, 2011. doi:  10.1016/j.tet.2011.12.013

PMCID: PMC3358821

NIHMSID: NIHMS344972

Acid-Facilitated Debenzylation of N-Boc, N-Benzyl Double Protected 2-Aminopyridinomethylpyrrolidine Derivatives

Haitao Ji,^1,2 Qing Jing,¹ Jinwen Huang,^1,3 and Richard B. Silverman^1,*

¹Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, and Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113

^*Correspondence to the Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, Phone: 847-491-5653, Email: ude.nretsewhtron.mehc@namgA

²Current address: Department of Chemistry, University of Utah, Salt Lake City, UT 84112-0850

³Current address: Shanghai HotMed Sciences Co., Ltd., Shanghai Zhangjiang Hi-Tech, Park,211-214 NO.518, Bibo Road, Shanghai, China

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Abstract

2-Aminopyridinomethyl pyrrolidines represent a class of highly potent and selective neuronal nitric oxide synthase inhibitors. Conditions for a Mitsunobu reaction of a naphthol and a hindered secondary alcohol were optimized to give good to excellent yields. A key step in the synthesis of these inhibitors is the deprotection of the benzyl group from the N-Boc and N-Bn double protected 2-aminopyridine ring at a late stage of the synthesis, which has been proven difficult in our previous syntheses. Acetic acid was found to facilitate the N-Bn deprotection.

Keywords: 2-Aminopyridinomethyl pyrrolidines, Mitsunobu reaction, N-Benzyl deprotection, Palladium-catalyzed hydrogenation