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Creators/Authors contains: "Parella, Ramarao"

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  1. A highly enantio- and diastereoselective method for the synthesis of functionalized chroman-2-ones and chromanes was achieved by using an organocatalytic domino Michael/hemiacetalization reaction of aliphatic aldehydes and ( E )-2-(2-nitrovinyl)phenols followed by a PCC oxidation and dehydroxylation, respectively. Using the modularly designed organocatalysts (MDOs) self-assembled from cinchona alkaloid derivatives and amino acids in the reaction media, the title products were obtained in good to high yields (up to 97%) and excellent diastereoselectivities (up to 99 : 1 dr) and enantioselectivities (up to 99% ee). 
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  2. Abstract Natural products are the great sources of drugs and leading compounds in drug discovery, as it has been estimated that most of the current medicines are derived from natural products. Total synthesis of natural products, especially those of biological activities, has been an important part of organic chemistry, which, besides its potential practical utilities, also provides new inspirations and novel synthetic methodologies. Over the past two decades, organocatalysis has been shown to be very effective in controlling the stereochemistry of the reaction products and has found many applications in the asymmetric synthesis of natural products and related compounds. In this review we will attempt to summarize some applications of asymmetric organocatalysis in the total synthesis of natural products and related compounds in the past seven years. 
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  3. The domino Michael/Michael reaction between ( E )-7-aryl-7-oxohept-5-enals and trans -cinnamaldehydes was investigated by using modularly designed organocatalysts (MDOs). It was found that both the enamine and iminium catalytic modes of the MDOs are switchable and can be individually switched on and off by using appropriate combinations of the precatalyst modules and the reaction conditions. When both the enamine and iminium catalysis modes of the MDOs are switched on, the desired domino reaction products can be obtained in good yields and stereoselectivities under optimized conditions. 
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