Extended hückel theory—v : Cumulenes, polyenes, polyacetylenes and cn

This Minireview provides a critical account of the development of allene-containing advanced functional materials, starting with the design and synthesis of stable and enantiopure building blocks. A variety of systems, including shape-persistent macrocycles, foldamers, polymers, charge-transfer chromophores, dendrimers, liquid crystals, and redox-switchable chiral chromophores are discussed from the viewpoint of their syntheses, properties, and potential applications. The goal of this Minireview is to inspire new uses of enantiopure allenes for the rational design of advanced materials.

Allenes in Molecular Materials

The conventional procedures for preparing optically active axially chiral allenes generally require stoichiometric chiral sources as either substrates or reagents. On the other hand, examples of catalytic asymmetric synthesis of axially chiral allenes are rare and it is a relatively underdeveloped area in synthetic organic chemistry. In this review article, various methods for preparing enantiomerically enriched axially chiral allenes using substoichiometric chiral sources are surveyed. Some reactions with stoichiometric but recoverable chiral sources are also mentioned. Most of the asymmetric reactions in these categories are transition-metal-catalyzed reactions, and there are a few examples of organocatalytic reactions. In addition, some enzymatic/microbial systems are also known.

Catalytic enantioselective synthesis of axially chiral allenes

While one-carbon central chirality of organic molecules has been recognized and extensively studied for more than a century, far less attention has been paid to three-carbon axial chirality of allenes, although they exist in nature with interesting biological activity and have been demonstrated with great synthetic potentials. However, remarkable progress has been made in this field in recent years, giving rise to axially chiral allenes with a wide range of functionalities with practical enantioselectivity. This review provides a concise account of enantioselective syntheses of axially chiral allenes with a selection of published protocols.

https://pubs.rsc.org/en/content/articlepdf/2014/qo/c4qo00208c

Conquering three-carbon axial chirality of allenes

Optical activity in the biaryl series

WE have succeeded in verifying the prediction made by van't Hoff in 1875, but hitherto unverified, that unsymmetrically substituted allenes, would be found to exhibit enantiomorphism.

Peter Maitland

Papers

Experimental Demonstration of the Allene Asymmetry

219. Resolution of an allene hydrocarbon into optical antipodes by asymmetric catalysis

366. The condensation of fluorene with acetone. Part II