[reaction: see text] We report a new enantioselective synthesis of (-)-alpha-kainic acid from d-serine methyl ester hydrochloride, based on a (-)-sparteine-mediated asymmetric deprotonation of an intermediate carbamate that, by stereospecific anti S(N)'S(E)' intramolecular cycloalkylation, leads to the pyrrolidine ring precursor of (-)-alpha-kainic acid, in high yield and diastereoselectivity. The intermediate pyrrolidine was further transformed to (-)-alpha-kainic acid in three steps.
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http://dx.doi.org/10.1021/ol0485666 | DOI Listing |
Chemistry
March 2015
Graduate School of Pharmaceutical Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka 812-8582 (Japan) http://green.phar.kyushu-u.ac.jp.
An increased supply of scarce or inaccessible natural products is essential for the development of more sophisticated pharmaceutical agents and biological tools, and thus the development of atom-economical, step-economical and scalable processes to access these natural products is in high demand. Herein we report the development of a short, scalable total synthesis of (-)-α-kainic acid, a useful compound in neuropharmacology that is, however, limited in supply from natural resources. The synthesis features sequential platinum-catalyzed direct allylic aminations and thermal ene-cyclization, enabling the gram-scale synthesis of (-)-α-kainic acid in six steps and 34% overall yield.
View Article and Find Full Text PDFAcc Chem Res
December 2014
Sorbonne Universités, UPMC Univ Paris 06 , UMR 8232, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France.
CONSPECTUS: Lactones and lactams are a well-known class of natural products and can be used as building blocks in organic synthesis. In addition, they can be found in many natural sources and synthetic drugs and have a broad range of biological or odorant properties. Chemists can create these useful compounds through palladium catalysis, which is a highly efficient tool for organic synthesis and is conveniently functional group tolerant.
View Article and Find Full Text PDFJ Org Chem
April 2013
Division of Natural Products Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, India 500 007.
The total synthesis of (-)-α-Kainic acid is accomplished using a linear strategy involving Noyori asymmetric reduction and chirality transfer through Ireland-Claisen rearrangement as key steps.
View Article and Find Full Text PDFChemistry
October 2012
Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China.
Org Lett
May 2012
Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Road Zu Chong Zhi, Zhangjiang Hi-Tech Park, Shanghai 201203, P.R. China.
An enantioselective synthesis of (-)-(α)-kainic acid in 15 steps with an overall yield of 24% is reported. The pyrrolidine kainoid precursor with the required C2/C3 trans stereochemistry was prepared with complete diastereoselectivity via an unprecedented SmI2-catalyzed intramolecular [3 + 2] cycloaddition reaction of an aryl cyclopropyl ketone and an alkyne. Double bond isomerization was then employed to set the remaining stereochemistry at the C4 position en route to (-)-(α)-kainic acid.
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