Puckering the Planar Landscape of Fragments: Design and Synthesis of a 3D Cyclobutane Fragment Library.

"Conflict of interest The authors declare no conflict of interest."

"This work was funded by the European Union's Framework Programme for Research and Innovation Horizon 2020 (2014–2020) under the Marie‐Skłodowska‐Curie grant agreement number 675899 (“Fragment based drug discovery Network, FRAGNET”) and under the grant agreement number 777828 (“The best online drug discovery platform. Building the Ultimate chemical database for drug discovery”). We thank Robert Kiss and Attila Wootsch for helpful discussions and support. We would like to thank Bas de Boer, Florian van Vugt, Emylie Nguyen and Fariëlle Boldewijn for their involvement in synthesis. We are grateful to Hans Custers for HRMS and nephelometry measurements, Tom Dekker for assistance with radar plots and nephelometry, and Elwin Janssen for assistance with NMR analysis."