Pd-catalyzed reductive cleavage of NN bond in dibenzyl-1-alkylhydrazine-1,2-dicarboxylates with PMHS: application to a formal enantioselective synthesis of (R)-sitagliptin
摘要:
An environmentally benign approach involving Pd-catalyzed reductive N-N bond cleavage in dibenzyl-1-alkylhydrazine-1,2-dicarboxylates leading to the synthesis of N-(tert-butoxy)carbamates under very mild conditions has been described. PMHS serves as an inexpensive source of hydride in MeOH/deionized H2O medium. This protocol has been successfully applied in the formal synthesis of (R)-sitagliptin, an anti-diabetic drug. (C) 2015 Elsevier Ltd. All rights reserved.
An octahedral bis-cyclometalated iridium(III) complex catalyzes the enantioselective α-amination of aldehydes with catalyst loadings down to 0.1 mol%. In this metal-templated design, the metal serves as a structural center and provides the exclusive source of chirality, whereas the catalysis is mediated through the organic ligand sphere.