Synthesis and Application of New, Optically Active Compounds as Catalysts and Ligands in Enantioselective Reactions

Abstract

Abstract

Highly efficient stereoconservative syntheses of new, bifunctional atropisomeric organocatalysts

“…33 On the other hand we have described high conformational stabilities of numerous α,o,o′-trisubstituted 1-phenylpyrrole type atropisomers, [28][29][30][31][32][33][34] and stereochemical lability was observed only in the cases where a tricyclic intermediate with a low rotational barrier (such as 9, Scheme 4) could be formed during the modification of the substituents. Therefore we suppose that during the formation of the diamide 10, the activated acyl group of compound (S a )-6b may react with the electron-rich amide function situated in the pyrrole α-position, providing an isoimidium salt (9) which is quite similar to several known compounds, 35,36 and the formation of this stereochemically labile tricyclic intermediate might be responsible for the racemization.…”

“…[28][29][30] We envisaged the combination of the atropisomeric 1-phenylpyrrole structure with thiourea and tertiary amine functions in one molecule to provide a new class of bifunctional organocatalyst having the potential to produce a synergistic effect in asymmetric transformations. Two types of organocatalyst were designed: a series with a direct connection between the thiourea moiety and the benzene ring of the biaryl skeleton (type 1, Scheme 2) to produce a relatively rigid structure, and another in which a methylene group is inserted between the thiourea function and the atropisomeric aromatic skeleton (type 2).…”

Racemization-free synthesis of atropisomeric 1-phenylpyrrole based diamines using diphenylphosphoryl azide

“…6 Recently, successful applications of 1-phenylpyrrole derived amino alcohols as highly efficient ligands in asymmetric transformations have been published. [7][8][9][10] An enantiopure amine can be prepared by resolution of the racemic mixture, although it is usually more convenient to synthesize the individual enantiomer from an enantiomerically pure key intermediate. 11 The synthesis of the dicarboxylic acid intermediate of numerous enantiopure atropisomeric 1-phenylpyrrole derived amino alcohols was elaborated upon several years ago in our laboratory 12 via o, a-dimetalated species.…”

Synthesis and Recovery of Pyridine- and Piperidine-based Camphorsulfonamide Organocatalysts Used for Michael Addition Reaction

“…Undoubtedly, using a catalytic amount of chiral controller is an elegant and economically attractive way to introduce chirality into a molecule. Among enantioselective reactions, methods based on metal-free chiral organocatalysts have become more significant [1][2][3]. We can state that asymmetric organocatalysis is one of the most rapidly growing research areas in synthetic organic chemistry [4,5].…”