Asymmetric Aldol Reaction of Allenoates: Regulation for the Selective Formation of Isomeric Allenyl or Alkynyl Aldol Adduct

One-Pot Tandem Nickel-Catalyzed α-Vinyl Aldol Reaction and Cycloaddition Approach to [1,2,3]Triazolo[1,5-a]quinolines

A one-pot tandem approach to [1,2,3]triazolo[1,5-a]quinolines was developed from (E)-β-chlorovinyl ketones and 2-azidoaryl carbonyls using a sequence of α-vinyl aldol and azide-alkyne cycloaddition reactions. In particular, the intramolecular azide-alkyne cycloaddition of allenol intermediates was readily promoted by a synergistic action of NEt₃ and nickel catalysts. Given that the [1,2,3]triazolo[1,5-a]quinolines are useful synthetic precursors to α-diazoimines through ring-chain isomerization process, the subsequent denitrogenative transformations should provide ready access to valuable heterocyclic compounds.

Regioselective direct sulfenylation of glycals using arylsulfonyl chlorides in the presence of triphenylphosphine: access to C2-thioaryl glycosides

Cheap and easily available arylsulfonyl chlorides as a sulfur source reductively couple with glycals in the presence of triphenylphosphine to afford C2-thioaryl glycosides.

Deciphering the Chameleonic Chemistry of Allenols: Breaking the Taboo of a Onetime Esoteric Functionality

The allene functionality has participated in one of the most exciting voyages in organic chemistry, from chemical curiosities to a recurring building block in modern organic chemistry. In the last decades, a special kind of allene, namely, allenol, has emerged. Allenols, formed by an allene moiety and a hydroxyl functional group with diverse connectivity, have become common building blocks for the synthesis of a wide range of structures and frequent motif in naturally occurring systems. The synergistic effect of the allene and hydroxyl functional groups enables allenols to be considered as a unique and sole functionality exhibiting a special reactivity. This Review summarizes the most significant contributions to the chemistry of allenols that appeared during the past decade, with emphasis on their synthesis, reactivity, and occurrence in natural products.

Allenoate Prenucleophiles: A Triply Diastereoselective Approach to β-Hydroxy Esters Containing All-Carbon α-Quaternary Centers

Allenyl esters activated by titanium(IV) underwent additions to a wide range of aldehydes in high regio- and diastereoselectivities leading to products containing an all-carbon quaternary center bearing an α-vinyl group that was installed with high selectivity for the Z-geometry. An aldol product was also converted to an indanone offering a new route to this important compound class. Product triple diastereoselectivity has been rationalized using a concerted transition-state model.

Synthesis of 2,3-allenylamides utilizing [1,2]-phospha-Brook rearrangement and their application to gold-catalyzed cycloisomerization providing 2-aminofuran derivatives

An efficient synthetic method for 2,3-allenylamides having an oxygen functionality at the 2-position was newly developed by utilizing the [1,2]-phospha-Brook rearrangement under Brønsted base catalysis.

Chirality transfer in metal-catalysed intermolecular addition reactions involving allenes

This review covers chirality transfer in metal-catalysed intermolecular addition reactions involving allenes, including axial-to-central chirality transfer, asymmetric catalysis and racemization.

2-Trifluoromethylthiolation of glycals

The direct 2-trifluoromethylthiolation of glycals has been realized for the first time, benefiting the carbohydrate-based drug discovery.