A Gold(I)-Catalyzed Domino Coupling of Alcohols with Allenes Enables the Synthesis of Highly Substituted Indenes

A New Method of Constructing Methyleneindene and Quinoline Frameworks from Methylenecyclopropanes

In this paper, we have established an operationally convenient protocol for the rapid construction of polysubstituted methyleneindene and quinoline derivatives under mild conditions. This new synthetic method is achieved through the conversion of acetyl-substituted methylenecyclopropanes with TsOH ⋅ H2O and ortho-amino-substituted methylenecyclopropanes with aromatic aldehyde and TsOH ⋅ H2O, respectively. A variety of transformations of the obtained products was demonstrated. The plausible reaction mechanisms were also proposed.

Reagent-Controlled Regioselective Intramolecular [2+2] Cycloaddition between Vinylsilanes and Allenes

This paper provides the first report of the intramolecular [2+2] cycloaddition of vinylsilane. The [2+2] cycloaddition of allenes is a useful reaction that can synthesize cyclobutanes. However, no previous works have attempted to control the regioselectivity between the two double bonds of allenes only by changing the reaction conditions, although there have been some reports of the regioselective [2+2] cycloaddition of allenes by changing the substrate. In this study, we have succeeded in controlling intramolecular [2+2] cycloaddition reactions at the proximal and distal positions of allenes simply by changing the reaction conditions. We found that the atomic radius of silicon is very important for perfect control of the reaction's sites. The structures of all key compounds were determined by the crystal sponge method which could identify the structures of liquid compounds.

Rh-Catalyzed cyclization of 2,3-allenoic acids in the presence of 2,3-allenols

Herein we report a [Cp*RhCl₂]₂-catalyzed coupling cyclization of two different classes of allenes with 2,3-allenoic acids affording 2(5H)-furanone skeletons of products and 2,3-allenols forming a conjugated (E)-enal or enone functionality to the β-position of the 2(5H)-furanones. These products are important building blocks for the syntheses of potentially bioactive compounds. The reaction proceeded via the nucleometalation, insertion, and stereodefined 1,4-H delivery carried by rhodium.

Gold(i)-catalyzed diastereoselective synthesis of 1-α-oxybenzyl-1H-indenes

The gold(i)-catalyzed oxycyclization of β-aryl monosubstituted o-(alkynyl)styrenes gives rise to 1-α-methoxy or 1-α-hydroxybenzyl-1H-indenes in a diastereospecific way.

Facile access to functionalized indenes and fused quinolines by regioselective 5-enolexo-dig Michael addition and cyclization reactions

Herein we report a facile approach to synthesise multi-substituted indenes and cyclopenta[b]quinolines under mild conditions.