A molecular machine directs the synthesis of a catenane

Precise mechanical manipulation of molecules is inherently difficult due to random thermal motion. While directed movement on the molecular scale has been achieved, using it to impose specific, especially energetically disfavored, shapes on molecules and construct mechanically interlocked structures remains a fundamental challenge. Here, we report the synthesis of a catenane enabled by a molecular motor that winds molecular strands into discrete entangled structures, each defined by a specific number of mechanical crossings. Light energy drives unidirectional motor rotation, enabling path-dependent control over a sequence of thermodynamically disfavored yet mechanically distinct and kinetically stable winding states, which are covalently captured and subsequently released to yield a catenane. This machine-directed approach offers a general proof-of-concept strategy for the template-free construction of mechanically interlocked molecules.