An efficient, palladium-catalyzed, decarboxylative [4 + 2]-cycloaddition of 4-vinyl benzoxazinanones with carboxylic acids has been developed with the employment of P-chiral monophosphorus ligand BI-DIME, affording a series of structurally diverse 3,4-dihydroquinolin-2-ones bearing two contiguous stereogenic centers in moderate to good yields with good to excellent stereoselectivities.
A highly
efficient synthetic approach to unnatural chiral β-Ar,Ar′-α-amino
acid esters bearing two contiguous stereogenic centers has been developed.
The first enantioselective 1,6-conjugate addition of glycine Schiff
bases to para-quinone methides was achieved using
a Cu(CH3CN)4BF4/Ph-Foxap catalytic
system (1 mol %). The reaction proceeded smoothly to generate corresponding
products in high yields with excellent diastereoselectivities (up
to 99:1) and enantioselectivities (up to >99% ee). Subsequent reduction
delivered enantiopure unnatural amino alcohols, which were utilized
for the synthesis of novel chiral ligands.
An efficient [2 + 2] annulation strategy that isothiourea catalyst homobenzotetramisole (HBTM)-catalyzed Mannich/lactamization cascade reaction of carboxylic acids with isatin-derived ketimines has been disclosed. This protocol affords a range of structurally diverse spirooxindole blactams bearing two vicinal stereogenic centers in good to high yields with good to excellent stereoselectivities.
A facile metal-free synthesis of 2-aminothiophene derivatives by the reaction of 2-ynals with thioamides in alcohols has been developed. This transformation allows the assembly of 2-aminothienyl ether derivatives via a well-designed aldol condensation/regioselective intramolecular cyclization/conjugate addition cascade reaction and provides a straightforward synthetic protocol for constructing 2,3,5-trisubstituted 2-aminothiophenes.
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.