Automated Stereocontrolled Assembly-Line Synthesis of Organic Molecules

Abstract

Automation has fuelled dramatic advances in fields such as proteomics and genomics (e.g., in preparation of proteins and nucleic acids),1,2 enabling non-experts to prepare, test and analyse complex biological molecules. However, the field of automated organic synthesis lags far behind, partly because of the complexity and variety of organic molecules. As a result, only a handful of relatively simple organic molecules, requiring a small number of synthetic steps, have been made in an automated fashion. Herein, we report an automated assembly-line synthesis that allows iterative, stereocontrolled formation of C(sp3)–C(sp3) bonds with high stereochemical fidelity and reproducibility, enabling access to complex organic molecules even by non-synthesis experts. This was achieved on a commercially available robotic platform capable of handling air sensitive reactants and performing low temperature reactions, which enabled six sequenced one-carbon homologations of organoboron substrates to be performed iteratively without human intervention. Together with other automated functional group manipulations, this methodology has been exploited to rapidly build the core fragment of the natural product (+)-kalkitoxin, thus leading the way towards automated organic synthesis.