Absolute Asymmetric Synthesis: The Origin, Control, And Amplification Of Chirality

One of the fundamental and intriguing aspects of life is the homochirality of the essential molecules. From the early days of stereochemistry, the origin of chirality in biological systems has been a challenge to the chemical sciences and numerous theories and experiments have been reported. Despite the great progress in asymmetric synthesis, there are only a few genuine absolute asymmetric syntheses known today. Novel approaches based on the interplay of molecular biology, organic chemistry, and supramolecular sciences have resulted in synthetic molecules that show amplification, autocatalysis, or self-replication and these systems are pertinent to the question as to how to amplify a small stereochemical bias. In this review absolute asymmetric synthesis-including many failures towards this goal-will be discussed with the emphasis on photochemistry with circularly polarized light and conversions in chiral crystals. Amplification mechanisms through autocatalytic systems, liquid crystalline materials, and polymers will also be described.