Formation of γ-Lactones through CAN-Mediated Oxidative Cleavage of Hemiketals
作者:Alexander M. Jacobine、Weimin Lin、Bethany Walls、Charles K. Zercher
DOI:10.1021/jo801258h
日期:2008.9.19
The generation of substituted gamma-lactones can be accomplished through application of a tandem chain extension-aldol reaction, followed by CAN-mediated oxidative cleavage of the aldol product. The oxidative cleavage requires the intermediacy of a hemiketal and the presence of an alpha-heteroatom. Formation of the gamma-lactone through the oxidative cleavage is used to assign stereochemistry of the
Stereoselective Formation of a Functionalized Dipeptide Isostere by Zinc Carbenoid-Mediated Chain Extension
作者:Weimin Lin、Cory R. Theberge、Timothy J. Henderson、Charles K. Zercher、Jerry Jasinski、Ray. J. Butcher
DOI:10.1021/jo801993k
日期:2009.1.16
The application of a zinc carbenoid-mediated chain-extension reaction to a functionalized peptide isostere is reported. The cleavage site of human CVM protease was utilized as a target for testing the synthetic methodology. The utility of this chain-extension reaction is demonstrated in the preparation of an amino acid-derived alpha-unsubstituted gamma-keto ester, which is incorporated into a framework that mimics a tetrapeptide. The identification of a suitable protecting group strategy facilitated the application of a tandem reaction for the incorporation of an alpha-side chain, and the use of an oxazolidinone auxiliary provided excellent diastereocontrol in a tandem chain-extension-aldol reaction. Stereoselectivity of the tandem chain-extension-aldol reaction was determined through application of a CAN-mediated oxidative cleavage reaction.
PHARMACEUTICAL COMPOSITION COMPRISING AN ESTER OF 5-AMINOLEVULINIC ACID AS PHOTOCHEMOTHERAPEUTIC AGENT AND A MUCOADHESIVE AGENT
申请人:Photocure ASA
公开号:EP1311259B1
公开(公告)日:2005-06-15
Studies towards complex bridged alkaloids: regio- and stereocontrolled enolate chemistry of 2,5-diketopiperazines
作者:Mark Pichowicz、Nigel S. Simpkins、Alexander J. Blake、Claire Wilson
DOI:10.1016/j.tet.2008.02.020
日期:2008.4
N-protected diketopiperazines (DKPs) via enolate intermediates has been studied. The enolate reactions were highly diastereocontrolled, leading to enantiopure DKP products if chiral amino acid precursors were employed, and giving racemic products, starting with centrosymmetric DKPs, even when a chiral lithium amide base was used to generate the lithium enolate. With unsymmetrical DKPs derivedfrom proline
Synthesis towards complex bridged alkaloids derived from diketopiperazines: a cationic cascade approach to stephacidins, paraherquamides and related systems
作者:Mark Pichowicz、Nigel S. Simpkins、Alexander J. Blake、Claire Wilson
DOI:10.1016/j.tetlet.2006.09.046
日期:2006.11
Regioselective enolate formation, followed by stereoselective electrophilic quenching of unsymmetrical proline-derived diketopiperazines (DKPs), enabled the synthesis of variously substituted DKPs, including one substrate which could be further substituted and cyclised to give the bicyclo[2.2.2]diazaoctane core structure present in paraherquamide and stephacidin natural products.