A series of acid-labile, optically pure ε-substituted δ-ketal-β-hydroxy esters were obtained by a Ru-SunPhos catalyzed asymmetric hydrogenation of the corresponding ε-substituted δ-ketal-β-keto esters. CaCO(3) played a dual role in the hydrogenation reaction--removing the acid generated during the formation of the catalyst and maintaining the activity of the catalyst.

Site-selective transition-metal-catalyzed mono-deboronative cross-couplings of 1,2-bis-boronic esters are valuable methods for the synthesis functionalized organoboron compounds. However, such limited to reaction sterically less hindered primary boronic ester. Herein, we report a nickel/photoredox-catalyzed arylation that is selective coupling more secondary/tertiary position. This achieved by ...

New DKR type: An N-heterocyclic carbene (NHC)-catalyzed dynamic kinetic resolution of racemic α-substituted β-keto esters has been developed. This method relies on the epimerization of an NHC-enol intermediate before subsequent aldol/acylation events. Highly substituted β-lactones are produced in good yield with good to excellent selectivities (see scheme).

Research Question: Does in vitro exposure of preimplantation mouse embryos to the ketone bodies β-hydroxybutyrate (βOHB) and acetoacetate (AcAc) impact post-transfer fetal placental gene expression?DesignBlastocysts cultured with or without 2 mmol/L βOHB alone (‘βOHB’) combined 0.8 AcAc (‘Keto’) underwent embryo transfer. Transcriptional profiles sexed E14.5 placentae, liver, brain were examine...

The activation of the α-carbons of carboxylic esters and related carbonyl compounds to generate enolate equivalents as nucleophiles is one of the most powerful strategies in organic synthesis. We reasoned that the horizons of chemical synthesis could be greatly expanded if the typically inert β-carbons of saturated esters could be used as nucleophiles. However, despite the rather significant fu...

We have previously shown that plasma high density lipoproteins (HDL) stimulate release of prostacyclin, measured as its stable metabolite, 6-keto-PGF1 alpha, by cultured porcine aortic endothelial cells. The present experiments were designed to elucidate the contribution of HDL lipids to endothelial cellular phospholipid pools and to prostacyclin synthesis. In experiments with reconstituted HDL...

Site-directed mutagenesis in combination with Fourier transform infrared difference spectroscopy has been used to study how hydrogen bonding modulates the electronic and physical organization of P700, the primary electron donor in photosystem I. Wild-type PS I particles from Chlamydomonas reinhardtii and a mutant in which ThrA739 is changed to alanine [TA(A739) mutant] were studied. ThrA739 is ...

Oxalic acid dihydrate as a green, mild and efficient catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives from the reaction between β-keto esters (methyl or ethyl acetoacetate), aromatic aldehyde (benzaldehye derivatives) and urea or thiourea under thermal and solvent-free conditions with excellent yields and short reaction time is st...

We report a method for the synthesis of α-diazo-β-keto esters, phosphonates and sulfones via acylation of corresponding diazomethyl anions with N-acylbenzotriazoles. The N-o-amino-acylbenzotriazoles exhibited an unprecedented transphosphorylation reaction leading to diazoacetyl phenylphosphoramidates.