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This review seeks to provide coverage on the recent advances in chiral squaramide-catalyzed asymmetric transformations and their applications in the synthesis of a variety of chiral biologically active compounds. It aims to give an overview highlighting the new reaction types and enantioenriched medicinal scaffolds developed in the last few years. [ABSTRACT FROM AUTHOR]

A more practical and efficient catalytic asymmetric chlorolactonization of styrene-type carboxylic acids with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) using C3-symmetric cinchonine-squaramide (CSCS) as organocatalyst has been developed. A series of chiral chloro-substituted isochroman-1-ones was obtained in excellent yields (up to 95%) and enantioselectivities (up to 99% ee), whwereby the results for chloro-substituted isochroman-1-ones are the best ever achieved. The catalyst can be recovered and reused for six cycles. Moreover, the chlorolactonization product 3b was further transformed to optically active bicyclic isochroman-1-one derivatives in high yield without losing the enantioselectivity. Furthermore, compounds 3e and 2n proved to be highly potent inhibitors of the HIV-1 in TZM-bl cells. [ABSTRACT FROM AUTHOR]

Abstract: A set of BINOL–quinine–squaramides were synthesized, and then used as organocatalysts to promote the catalytic enantioselective Michael addition reaction of 2-hydroxy-1,4-naphthoquinone to nitroalkenes with excellent yields and ees (up to 99% yield and 93% ee) at low catalyst loading (0.5mol%). [Copyright &y& Elsevier]

Review: [46 refs. [ABSTRACT FROM AUTHOR]

The tandem enantioselective Michael addition/cyclisation reaction of malononitrile and nitrovinylphenols was catalysed by a recoverable C 3 -symmetric cinchonine-squaramide organocatalyst 1a to afford the 2-amino-4 H -chromene-3-carbonitrile derivatives in excellent yields (up to 95%) and with excellent enantioselectivities (up to 98% ee) under mild reaction conditions. Furthermore, this catalyst can be easily recovered four times without loss in activity or enantioselectivity. [ABSTRACT FROM AUTHOR]

The article presents a chemical equation related to the article "BINOL-Quinine-Squaramides as Efficient Organocatalysts for the Asymmetric Michael Addition of 2-Hydroxy-1,4-naphthoquinone to Nitroalkenes" by E. Zhou, B. Liu and C. Dong, published in the periodical "Tetrahedron: Asymmetry" in 2014.

Abstract: A series of chiral bifunctional squaramide multiple H-bond donor organocatalysts have been designed and synthesized by the rational assembly of chiral privileged scaffolds of indanol and cinchona alkaloids. In the presence of 1mol% 1a, the asymmetric Michael addition reaction of 1,3-dicarbonyl compounds to nitroolefins proceeded to provide the product in high yields (up to 92%) and with good to high ee values (up to 96%). The additional H-bond in this squaramide system plays a crucial role in enhancing the enantioselectivity. [Copyright &y& Elsevier]

Screening experiments show, that the squaramide catalyst (SQA) gives the best results for the Morita-Baylis-Hillman reaction of isatins with acrylates to form the corresponding alcohols in high yields with enantioselectivities of up to 95%. [ABSTRACT FROM AUTHOR]

The asymmetric synthesis of a wide range of chiral amino acid derivatives in excellent yields and enantioselectivities (up to 99% e.e.) is reported. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to an article on enantioselective addition reaction of 1,3-dicarbonyl compounds to nitroalkenes catalyzed by Chiral BINOL-Quinine-Squaramide by authors B. Liu and others, published in the 2013 issue of the journal "Tetrahedron: Asymmetry."

The article presents the steps of chemical reactions involved in the addition of 1,3-dicarbonyl compounds to nitroolefins.