Abstract
Inherently chiral calix[4]arenes exhibit broad applications in asymmetric catalysis, chiral recognition, and materials science. However, their synthesis remains a significant challenge. Herein, we report a highly efficient method for the construction of calix[4]arenes with both axial and inherent chiralities through palladium/chiral norbornene (Pd/NBE*) cooperative catalysis. In this cascade reaction, the initial introduced axial chirality is dictated by Pd/NBE* cooperative catalysis, while the latter inherent chirality is controlled by the preestablished axial chirality via an unprecedented axial-to-inherent diastereoinduction process. This method employs ortho-calix[4]arene-tethered aryl iodides and β-substituted naphthyl bromides as starting materials, enabling the synthesis of a wide range of five- and six-membered benzo-fused calix[4]arenes with axial and inherent chiralities (29 examples) in one step with excellent enantioselectivities and diastereoselectivities. Preliminary studies of photophysical and chiroptical properties reveal that these axially and inherently chiral calix[4]arenes possess promising glum values, demonstrating their potential in developing new organic optoelectronic materials.
Supplementary materials
Title
SI of Enantioselective Synthesis of Calix[4]arenes with Axial and Inherent Chiralities via Palladium/Chiral Norbornene Cooperative Catalysis
Description
All reactions dealing with air- or moisture-sensitive compounds were performed in the argon-filled glove box or by standard Schlenk techniques in oven-dried reaction vessels under argon atmosphere. All NMR spectra were recorded on a Bruker spectrometer at 400 MHz or 600 MHz (1H NMR), 100 MHz or 150 MHz (13C NMR), 376 MHz or 565 MHz (19F NMR), 162 MHz or 243 MHz (31P NMR).
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