Catalyst Repurposing Sequential Catalysis by Harnessing Regenerated Prolinamide Organocatalysts as Transfer Hydrogenation Ligands
作者:Frederic Bourgeois、Jonathan A. Medlock、Werner Bonrath、Christof Sparr
DOI:10.1021/acs.orglett.9b04033
日期:2020.1.3
A catalyst repurposing strategy based on a sequential aldol addition and transferhydrogenation giving access to enantiomerically enriched α-hydroxy-γ-butyrolactones is described. The combination of a stereoselective, organocatalytic step, followed by an efficient catalytic aldehydereduction induces an ensuing lactonization to provide enantioenriched butyrolactones from readily available starting
Biocatalytic Synthesis of Homochiral 2-Hydroxy-4-butyrolactone Derivatives by Tandem Aldol Addition and Carbonyl Reduction
作者:Carlos J. Moreno、Karel Hernández、Samantha Gittings、Michael Bolte、Jesús Joglar、Jordi Bujons、Teodor Parella、Pere Clapés
DOI:10.1021/acscatal.3c00367
日期:2023.4.21
hydroxymethyltransferase (KPHMTEcoli), 2-keto-3-deoxy-l-rhamnonate aldolase (YfaUEcoli), and trans-o-hydroxybenzylidene pyruvate hydratase-aldolase from Pseudomonas putida (HBPAPputida) and (ii) subsequent 2-oxogroup reduction of the aldol adduct by ketopantoate reductase from E. coli (KPREcoli) and a Δ1-piperidine-2-carboxylate/Δ1-pyrroline-2-carboxylate reductase from Pseudomonas syringae pv. tomato DSM 50315
Silylation-Based Kinetic Resolution of α-Hydroxy Lactones and Lactams
作者:Robert W. Clark、T. Maxwell Deaton、Yan Zhang、Maggie I. Moore、Sheryl L. Wiskur
DOI:10.1021/ol402982w
日期:2013.12.20
A silylation-based kinetic resolution has been developed for alpha-hydroxy lactones and lactams employing the chiral isothiourea catalyst (-)-benzotetramisole and triphenylsilyl chloride as the silyl source. The system is more selective for lactones than lactams, and selectivity factors up to 100 can be achieved utilizing commercially available reagents.
A General Method for the Enantioselective Synthesis of Pantolactone Derivatives
作者:David A. Evans、Jimmy Wu、Craig E. Masse、David W. C. MacMillan
DOI:10.1021/ol026489d
日期:2002.10.1
An efficient enantioselective synthesis of beta,beta-dialkyl-gamma-substituted pantolactones has been achieved utilizing the cationic [Sc((S,S)-R-pybox)](Cl)(2)(+), R = Ph (9), t-Bu (10), complex in a catalyzed aldol reaction as the key step. The pantolactone derivatives are isolated in high enantiomeric excesses. [reaction: see text]