The most reliable method to determine the absolute configuration of chiral molecules is X‐ray crystallography, but small molecules can be difficult to crystallize. We report rapid co‐crystallization of tetraaryladamantanes with small molecules as different as n‐decane to nicotine to produce crystals for X‐ray analysis and the assignment of absolute configuration when the molecules are chiral. A screen of 52 diverse compounds gave inclusion in co‐crystals for 88 % of all cases and a high‐resolution structure in 77 % of cases. Furthermore, starting from three milligrams of analyte, a combination of NMR spectroscopy and X‐ray crystallography produced a full structure in less than three days using an adamantane crystallization chaperone that encapsulates the analyte at room temperature.

Bei der Einwirkung von Kohlendioxyd auf Aluminiumtrialkyle konnen je nach den Bedingungen 1) Tridkylcarbinole, 2) 1 Mol und 3) 2 Mol Carbonsaure erhalten werden. Auch bei der ersten Reaktion wird ahnlich wie bei der zweiten nur eine Al-C-Valenz ausgenutzt. Durch Nachoxydation im Falle 2) sind zusatzlich 2 Mol Alkohol zu gewinnen. SO2 liefert mit allen drei Al-C-Bindungen Sulfinsauren, insbesondere wenn man nach dem Prinzip der ,,umgekehrten Reaktionsfuhrung" arbeitet.

The most reliable method to determine the absolute configuration of chiral molecules is X‐ray crystallography, but small molecules can be difficult to crystallize. We report rapid co‐crystallization of tetraaryladamantanes with small molecules as different as n‐decane to nicotine to produce crystals for X‐ray analysis and the assignment of absolute configuration when the molecules are chiral. A screen of 52 diverse compounds gave inclusion in co‐crystals for 88 % of all cases and a high‐resolution structure in 77 % of cases. Furthermore, starting from three milligrams of analyte, a combination of NMR spectroscopy and X‐ray crystallography produced a full structure in less than three days using an adamantane crystallization chaperone that encapsulates the analyte at room temperature.

Achieving efficient capture, storage and release of small molecules is a challenge. Most materials that can harbor small molecules have been studied in the context of gas storage or separation. Formulations for hazardous reagents have only recently attracted attention, when organic compounds were discovered that encapsulate a broad range of guest molecules in crystals. Such encapsulating organic crystals (EnOCs) can suppress problematic properties of reagents and allow for controlled release in reaction mixtures. Unlike materials used for gas storage, which possess permanent porosity, their cavities are not held together by covalent or strong noncovalent interactions. Instead, EnOCs crystallize with the help of weaker packing forces. Substituted tetraaryladamantane octaethers can form high-loading inclusion compounds with reagents as guests, but they can also transition into tightly packed, solvate-free forms. Here we highlight the differences between EnOCs and known porous materials and discuss the potential of EnOCs as formulations in organic synthesis.

Cyclopentadiene (Cpd) is widely used as a starting material in organic and inorganic chemistry. In neat form, Cpd dimerizes, making it necessary to distill it prior to use to obtain fully reactive material. We have screened three different tetraphenyladamantane octaethers for their ability to act as encapsulating organic crystal (EnOC) hosts for Cpd. To this end, we also synthesized 1,3,5,7-tetrakis(3,5-dimethoxyphenyl)adamantane, a new octaether, dubbed iso-TDA. Only one of the octaethers was found to produce inclusion complexes with Cpd in the crystalline state. The encapsulated diene was stable for one month and showed full reactivity in a series of different synthetic transformations.