Recent progress in the synthesis of benzene and 1,3-cyclohexadiene derivatives, and heterocyclic compounds such as pyridines, pyridones, pyrans, pyrimidine diones, etc, has been reviewed. The general mechanistic aspects of the [2+2+2] cycloaddition reaction are discussed. The asymmetric variants of these reactions are also discussed along with the proposed models of asymmetric induction.

http://web4.uwindsor.ca/users/j/jlichaa/reference.nsf/0/10ff8b04ff3a317885256d88005720f6/$file/asc-2006-348-2307 2+2+2.pdf

[2+2+2] Cycloaddition Reactions Catalyzed by Transition Metal Complexes

Recent Developments in the Application of Oxazoline-Containing Ligands in Asymmetric Catalysis

Recent advances towards a development of novel transition-metal-catalyzed enantioselective [2+2+2] cycloadditions for the synthesis of axially chiral biaryls are reviewed. A number of efficient enantioselective biaryl syntheses were accomplished by chiral cobalt(I), iridium(I), and rhodium(I) complex catalyzed [2+2+2] cycloadditions. Furthermore, the enantioselective synthesis of axially chiral biaryls possessing non-biaryl axial chirality was also developed by using chiral rhodium(I) complexes as catalysts.

Transition-metal-catalyzed enantioselective [2+2+2] cycloadditions for the synthesis of axially chiral biaryls.

Transition metal-catalysed higher-order carbocyclisation reactions represent an important class of reactions due to their ability to construct complex polycyclic systems in a highly selective and atom-economical fashion. A key and striking feature with these transformations is the dichotomy in reactivity that a substrate displays with different transition metal complexes, which is akin to the manner enzymes direct terpene biosynthesis. This tutorial review details the historical development of higher-order carbocyclisation reactions, specifically the variants of [m+2+2] that involve carbon-based π-systems, where m = 2, 3 and 4, in the context of critical developments with various transition metal complexes.

Stereoselective transition metal-catalysed higher-order carbocyclisation reactions.

https://hal.archives-ouvertes.fr/hal-01929757/document

Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals

Catalytic enantioselective intermolecular [2 + 2 + 2] cycloaddition of an alkene and two alkynes

Effects of monodentate oxazoline ligands in Ni/Al-catalyzed regioselective cyclotrimerization of enones and alkynes

A nickel and aluminium system including monodentate oxazoline 
ligands catalyzed the regioselective cyclotrimerization of enones and 
alkynes.

Effects of Monodentate Oxazoline Ligands in Ni/Al‐Catalyzed Regioselective Cyclotrimerization of Enones and Alkynes.

A catalytic enantioselective intermolecular [2 + 2 + 2] cycloaddition of one molecule of alkene (enone) and two molecules of alkyne was developed in the presence of a nickel complex modified by chiral monodentate oxazoline ligands, which have not previously been used as chiral ligands for transition metals in asymmetric catalysts, and an aluminium phenoxide.

Hirokazu Kondo

Papers

Catalytic enantioselective intermolecular [2 + 2 + 2] cycloaddition of an alkene and two alkynes

Effects of monodentate oxazoline ligands in Ni/Al-catalyzed regioselective cyclotrimerization of enones and alkynes

Effects of Monodentate Oxazoline Ligands in Ni/Al‐Catalyzed Regioselective Cyclotrimerization of Enones and Alkynes.

Catalytic Enantioselective Intermolecular [2 + 2 + 2] Cycloaddition of an Alkene and Two Alkynes.