Dinuclear zinc cooperative catalytic three-component reactions for highly enantioselective synthesis of 3,3′-dihydrofuran spirooxindoles

A new dinuclear zinc cooperative catalytic enantioselective three-component reaction via a domino Knoevenagel/Michael/cyclization sequence has been developed.

Asymmetric [4+2] annulations to construct norcamphor scaffolds with 2-cyclopentenone via double amine–thiol catalysis

A double catalytic system combining chiral amine and 2-mercaptobenzoic acid is applied for α′,β-regioselective [4+2] annulations of 2-cyclopentenone with diverse activated alkenes.

An Asymmetric Organocatalytic Quadruple Domino Reaction Employing a Vinylogous Friedel-Crafts/Michael/Michael/Aldol Condensation Sequence

An organocatalytic quadruple cascade initiated by a Friedel-Crafts-type reaction is described. The (S)-diphenylprolinol trimethylsilyl ether catalyzed reaction yields highly functionalized cyclohexenecarbaldehydes bearing a 1,1-bis[4-(dialkylamino)phenyl]ethene moiety and three contiguous stereogenic centers. The reaction tolerates various functional groups and all products are obtained with very good diastereoselectivity and with virtually complete enantiomeric excess.

Organocatalytic diastereoselective synthesis of chiral decalines through the domino Claisen–Schmidt/Henry reaction

General and operative domino Claisen–Schmidt/Henry (CS/H) reaction has been revealed to obtain highly substituted chiral decalines in good yields with excellent ees and des by using push–pull enamine catalysis.

High-yielding sequential one-pot synthesis of chiral and achiral α-substituted acrylates via a metal-free reductive coupling reaction

A general process for the high-yielding synthesis of substituted chiral and achiral α-substituted acrylates was achieved through the sequential one-pot combination of a metal-free reductive coupling reaction followed by an Eschenmoser methylenation. The proline catalyzed reaction of Meldrum's acid, aldehydes and Hantzsch ester followed by methylenation was successful with Eschenmoser's salt in the presence of an alcohol solvent. Herein, we have shown the high-yielding synthesis of privileged building blocks from chiral/achiral α-substituted acrylates and shown them to be very good intermediates in the pharmaceuticals and natural products synthesis.

Design, synthesis and biological evaluation of optically pure functionalized spiro[5,5]undecane-1,5,9-triones as HIV-1 inhibitors

A single-step amino acid-catalyzed diastereoselective three-component synthesis of optically pure highly functionalized spiro[5,5]undecane-1,5,9-triones preferentially over the four stereoisomers was accomplished in very good yields with >99% ee/de. Preliminary cell culture-based in vivo screening on these molecules revealed that cis-1aca and cis-1jca are better lead compounds for HIV-1 treatment than the known antiretroviral drug azidothymidine (AZT).

Sequential one-pot combination of multi-component and multi-catalysis cascade reactions: an emerging technology in organic synthesis

Creating sequential one-pot combinations of multi-component reactions (MCRs) and multi-catalysis cascade (MCC) reactions is a challenging task that has already emerged as a new technology in synthetic organic chemistry. Through one-pot sequential combination of MCRs/MCC reactions, the chemical products (fine chemicals, agrochemicals and pharmaceuticals) that add value to our lives can be produced with less waste and greater economic benefits. Within this Emerging Area, we describe our recent developments and designs for sequential one-pot MCRs/MCC reactions to facilitate their realization as biomimetics in organic chemistry.

A general approach to chiral building blocks via direct amino acid-catalyzed cascade three-component reductive alkylations: formal total synthesis of HIV-1 protease inhibitors, antibiotic agglomerins, brefeldin A, and (R)-gamma-hexanolide

Multicatalysis cascade (MCC) process for the synthesis of highly substituted chiral building blocks (2-alkyl-CH-acids, 2-alkylcyclohexane-1,3-diones, 2-alkylcyclopentane-1,3-diones, and H-P ketone analogues) is presented based on the cascade three-component reductive alkylation's (TCRA) platform. Herein, we developed the high-yielding alkylation of a variety of CH-acids with (R)-glyceraldehyde acetonide/(S)-Garner aldehyde and Hantzsch ester through amino acid-catalyzed TCRA reaction without racemization at the alpha-position to carbonyl. Direct sequential combination of the L-proline-catalyzed TCRA reaction with other reactions like cascade alkylation/ketenization/esterification (A/K/E), alkylation/ketenization/esterification/alkylation (A/K/E/A), Brønsted acid-catalyzed cascade hydrolysis/lactonization/esterification (H/L/E), hydrolysis/esterification (H/E), hydrolysis/oxy-Michael/dehydration (H/OM/DH), and Robinson annulation (RA) of CH-acids, chiral aldehydes, Hantzsch ester, diazomethane, methyl vinyl ketone, various active olefins, and acetylenes furnished the highly functionalized chiral building blocks in good to high yields with excellent diastereoselectivities. In this context, many of the pharmaceutically applicable chiral building blocks were prepared via MCC reactions.

Direct amino acid-catalyzed cascade biomimetic reductive alkylations: application to the asymmetric synthesis of Hajos-Parrish ketone analogues

A direct amino acid-catalyzed chemo- and enantioselective process for the double cascade synthesis of highly substituted 2-alkyl-cyclopentane-1,3-diones, 2-alkyl-3-methoxy-cyclopent-2-enones and Hajos-Parrish (H-P) ketone analogs is presented via reductive alkylation chemistry. For the first time, we have developed a single-step alkylation of cyclopentane-1,3-dione with aldehydes/ketones and a Hantzsch ester through an organocatalytic reductive alkylation strategy. A direct combination of amino acid-catalyzed cascade olefination-hydrogenation and cascade Robinson annulations of cyclopentane-1,3-dione, aldehydes/ketones, a Hantzsch ester and methyl vinyl ketone furnished the highly functionalized H-P ketone analogues in good to high yields and with excellent enantioselectivities. Many of the reductive alkylation products have shown direct applications in pharmaceutical chemistry.