Site-selective benzoin-type cyclization of unsymmetrical dialdoses catalyzed by N-heterocyclic carbenes for divergent cyclitol synthesis

A highly site-selective N-heterocyclic carbene (NHC)-catalyzed benzoin-type cyclization of unsymmetrical dialdoses is developed to enable a divergent cyclitol synthesis. The choice of chiral NHCs and protecting groups affects the site-selectivity. The resulting inososes are converted into epi-, muco- and myo-inositol, and their chiral protected derivatives are formed in good yields

Catalytic Alkyne Arylation Using Amines as Traceless Directing Groups

By developing a Pd(0)/Mandyphos catalyst, we have achieved a three-component aminoarylation of alkynes to generate enamines, which upon hydrolysis yield either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes well-established pathways to enable the use of amines as traceless directing groups for C–C bond formation

Catalytic Alkyne Arylation Using Traceless Directing Groups

By using Pd0 /Mandyphos, we achieved a three-component aminoarylation of alkynes to generate enamines, which are then hydrolyzed to either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes established known pathways to enable the use of amines as traceless directing groups for C-C bond formation

Catalytic Alkyne Arylation Using Traceless Directing Groups

By using Pd0/Mandyphos, we achieved a three-component aminoarylation of alkynes to generate enamines, which are then hydrolyzed to either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes established known pathways to enable the use of amines as traceless directing groups for C−C bond formation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhe

Catalytic Alkyne Arylation Using Amines as Traceless Directing Groups

By developing a Pd(0)/Mandyphos catalyst, we have achieved a three-component aminoarylation of alkynes to generate enamines, which upon hydrolysis yield either <i>α</i>-arylphenones or <i>α</i>,<i>α</i>-diarylketones. This Pd-catalyzed method overcomes well-established pathways to enable the use of amines as traceless directing groups for C–C bond formation

Mild Organic Base-Catalyzed Primary Alcohol-Selective Aroylation Reaction Using N-Aroylcarbazoles for Underexplored Prodrugs

We report a highly primary alcohol-selective aroylation reaction using N-aroylcarbazoles (NAroCs). The aroylationproceeded smoothly in the presence of DBU, which most likely works as a general base catalyst in the reaction system. The synthetic utility was displayed in the primary alcohol-selective aroylation of complex drug molecules and natural products to their prodrugs. Stoichiometrically generated carbazole, the starting material of NAroCs could be easily recovered. We also established safer multigram and multidecagram scale preparation methods of NAroCs, which are easy-to-handle bench-stable reagents.</div

Enhanced Rate and Selectivity by Carboxylate Salt as a Basic Cocatalyst in Chiral N‑Heterocyclic Carbene-Catalyzed Asymmetric Acylation of Secondary Alcohols

The rate and enantioselectivity of chiral NHC-catalyzed asymmetric acylation of alcohols with an adjacent H-bond donor functionality are remarkably enhanced in the presence of a carboxylate cocatalyst. The degree of the enhancement is correlated with the basicity of the carboxylate. With a cocatalyst and a newly developed electron-deficient chiral NHC, kinetic resolution and desymmetrization of cyclic diols and amino alcohols were achieved with extremely high selectivity (up to <i>s</i> = 218 and 99% ee, respectively) at a low catalyst loading (0.5 mol %). This asymmetric acylation is characterized by a unique preference for alcohols over amines, which are not converted into amides under the reaction conditions