The asymmetric organocatalytic one‐pot synthesis of polyfunctionalized cyclohexanes is described. Starting from β‐keto esters, nitroalkenes and α,β‐unstaturated aldehydes and employing a bifunctional norephedrine‐based thiourea catalyst, six contiguous stereocenters including one quarternary center are generated. The one‐pot protocol follows a Michael/Michael/aldol addition sequence and affords the highly substituted cyclohexanes in moderate to very good yields (22–70%), diastereomeric ratios of dr>95:5 and excellent enantioselectivities of 91–99% ee.
The diastereo-and enantioselective synthesis of 3-acetyl-4-hydroxyisochroman-1-ones via an intramolecular trans-selective aldol reaction employing proline-type organocatalysts is described. Good yields (64-88%) and high stereoselectivities (87 to >95% de, 84-99% ee) are obtained, thus potentially enabling, for example, a new direct entry to carbazolelactone alkaloid natural products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.