Stereodivergent entry to β-branched β-trifluoromethyl α-amino acid derivatives by sequential catalytic asymmetric reactions

Abstract

Currently, conventional reductive catalytic methodologies do not guarantee general access to enantioenriched β-branched β-trifluoromethyl α-amino acid derivatives. Herein, a one-pot approach to these important α-amino acids, grounded on the reduction...

Enantioselective organocatalytic strategies to access noncanonical α-amino acids

“…Recently, our laboratories reported a conceptually new and stereodivergent approach to β-branched AAs by a sequential process involving the enantioselective transfer hydrogenation of Erlenmeyer–Plöchl substrates followed by the dynamic ring-opening of the resulting azlactones. 146 The realization of this tactic with trifluoromethylated substrates has disclosed a one-pot entry to β-branched, β-trifluoromethyl AA derivatives ( Scheme 51 ). The first step controls the configuration of the β-chirality centre and is performed using an HE and the Jacobsen-type thiourea 55.…”

Sulfoxonium Ylides in Aminocatalysis: An Enantioselective Entry to Cyclopropane-Fused Chromanol Structures

“…The intrinsic diastereomeric relationship between the transitions states leading to the cis - 8aa and to the trans - 8aa isomer justifies the requirement of different (i.e., not enantiomeric) catalytic structures for the two reactions (see the Supporting Information ). 20 …”