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Asymmetric syntheses of isoindoline carbamates have been successfully achieved through enzyme-mediated dynamic kinetic resolution processes and without requirement of metal or acid-base catalyst for the substrate racemization. Optically active carbamates were obtained in good yields and an excellent degree of stereoselectivity when Pseudomonas cepacia lipase (PSL) was used as biocatalyst, with diallyl or dibenzyl carbonates being both adequate reagents in alkoxycarbonylation reactions.

An efficient methodology for the preparation of the α-tetrasubstituted proline analog (S,S,S)-2-methyloctahydroindole-2-carboxylic acid, (S,S,S)-(αMe)Oic, and its enantiomer, (R,R,R)-(αMe)Oic, has been developed. Starting from easily available substrates and through simple transformations, a racemic precursor has been synthesized in excellent yield and further subjected to HPLC resolution using a cellulose-derived chiral stationary phase. Specifically, a semipreparative (250 mm × 20 mm ID) Chiralpak® IC column has allowed the efficient resolution of more than 4 g of racemate using a mixture of n-hexane/tert-butyl methyl ether/2-propanol as the eluent. Multigram quantities of the target amino acids have been isolated in enantiomerically pure form and suitably protected for incorporation into peptides., (Copyright © 2011 Wiley-Liss, Inc.)

Abstract: The orthopalladation of methyl arylglycinate derivatives has been studied. The reaction proceeds efficiently for different electron-withdrawing and electron-releasing substituents at the aryl ring. The carbonylation of the orthopalladated complexes affords, in a single step, substituted (1H)-isoindolin-1-one-3-carboxylates. These compounds constitute valuable synthetic intermediates and can be transformed diastereoselectively into octahydroisoindole-1-carboxylic acid derivatives, an important scaffold in the synthesis of many biologically active compounds. [Copyright &y& Elsevier]

We present here the results obtained in our study on organocatalytic enantioselective Michael addition reaction of acetone to different nitroolefines using (2R,3aS,7aS)-octahydroindole-2-carboxylic acid [(R,S,S)-Oic] as a new and suitable catalyst for this process. Computational calculations support the results obtained with (R,S,S)-Oic versus its diastereomeric form (S,S,S)-Oic. The final products are obtained in good yields and moderate enantioselectivities (up to 58% ee). [ABSTRACT FROM AUTHOR]

We present here the results obtained in our study on organocatalytic enantioselective Michael addition reaction of acetone to different nitroolefines using (2R,3aS,7aS)-octahydroindole-2-carboxylic acid [(R,S,S)-Oic] as a new and suitable catalyst for this process. Computational calculations support the results obtained with (R,S,S)-Oic versus its diastereomeric form (S,S,S)-Oic. The final products are obtained in good yields and moderate enantioselectivities (up to 58% ee). [ABSTRACT FROM AUTHOR]

Abstract: High yielding and remarkably selective alkylations of a suitably protected derivative of (2S,3aS,7aS)-octahydroindole-2-carboxylic acid are described. The fused bicyclic structure of this proline analogue greatly influences the stereochemical outcome of direct alkylation reactions taking place at the α-carbon and provides access to α-substituted analogues with retention of the configuration. The overall procedure allows the preparation of enantiopure α-substituted derivatives of this Oic isomer, suitably protected for their incorporation into peptides, in a straightforward manner. [Copyright &y& Elsevier]

Abstract: A high yielding and remarkably stereoselective α-methylation reaction of the (2S,3aS,7aS)-stereoisomer of octahydroindole-2-carboxylic acid, (S,S,S)-Oic, suitably protected is described. The severe steric hindrance imposed by the fused cyclohexane ring, which prevents the application of Seebach’s self-reproduction of chirality methodology, accounts for the formation of (S,S,S)-(αMe)Oic with high selectivity and retention of configuration. [Copyright &y& Elsevier]

Abstract: An improved strategy for the effective synthesis of enantiomerically pure (2R,3aS,7aS)-octahydroindole-2-carboxylic acid (Oic), based on the formation of a trichloromethyloxazolidinone derivative, has been developed. Additionally, the completely diastereoselective α-alkylation of such oxazolidinone provides a very convenient and concise route to enantiopure α-tetrasubstituted derivatives of this Oic stereoisomer. [Copyright &y& Elsevier]

Abstract: The preparation of the proline analogue (2S,3aS,7aS)-octahydroindole-2-carboxylic acid (Oic) and its enantiomer, (2R,3aR,7aR)-Oic, is described. A racemic precursor has been synthesized in good yield and subjected to HPLC resolution on a chiral column. The high efficiency of both the synthetic and chromatographic procedures has allowed the isolation of multigram quantities of each amino acid in enantiomerically pure form and suitably protected for use in peptide synthesis. [Copyright &y& Elsevier]

Asymmetric syntheses of isoindoline carbamates have been successfully achieved through enzyme-mediated dynamic kinetic resolution processes and without requirement of metal or acid–base catalyst for the substrate racemization. Optically active carbamates were obtained in good yields and an excellent degree of stereoselectivity when Pseudomonas cepacialipase (PSL) was used as biocatalyst, with diallyl or dibenzyl carbonates being both adequate reagents in alkoxycarbonylation reactions. [ABSTRACT FROM AUTHOR]