Development of an orthogonal, stereodivergent synthesis machinery programmable by light
Final Report Abstract
In summary in the course of this project the goal of developing a photoswitchable synthesis machine has not been realized. Even though there were some problems related to the synthesis of the machine I personally think that there is still a lot of potential for it. Changing the donor groups or designing different synthetic anchors might enable the success. Furthermore, a highly selective methodology for the preparation of P/chirogenic compounds has been developed. A broad functional group tolerance high yields and selectivities offer great potential for its application on a broader scale. On top of that efforts to unveil the mechanistic picture have been made and a potential intermediate has been identified, characterized and isolated. In further transformation it has been showcased that this new methodology can be used for the synthesis of various chiral phosphine oxides which find broad application in various fields of chemistry. Even the preparation of two enantiomers of a phosphine oxide were feasible due to the stereodivergent nature of the addition sequence of organometallic reagents. A revolves around a nanoratchet that comprises a molecular motor and a bismacrocycle with imines as labile connections. Unidirectional rotation of the motor around the central double bond promotes winding of the bismacrocycle entangling the tethers and creating species with various crossings that are different in energy. Higher number of crossings equals higher energy of the system. A thermal relaxation can occur through opening and closing of the imines. An equilibrium distribution can be shifted towards a certain photostationary state which I far from equilibrium. Apart from thermal equilibration an external nucleophile results in equilibration of the system as well. In this study sequential winding and sequential unwinding have been shown when an external nucleophile is omitted. In contrary non-sequence specific unwinding is observed in presence of nucleophiles such as butyl amine.
Publications
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“A light-fueled nanoratchet shifts a coupled chemical equilibrium”, Nature Nanotechnology
M. Kathan, S. Crespi, N. O. Thiel, D. L. Stares, J. de Boer, G. Pacella, T. van den Enk, P. Kobauri, G. Portale, C. A Schalley, Ben L. Feringa
