A simple one-pot multicomponent synthesis of an octahedral nanocontainer molecule

Abstract

A nearly quantitative 18-component synthesis of a nanocontainer, which is built up from six bowl-shaped cavitands that are connected together with 12 -CH¼N-CH 2 CH 2 -N¼CH-linkers, and its subsequent reduction are described. This nanocontainer has an estimated cavity volume of 1,700 Å 3 , large enough to encapsulate several smaller guest molecules or a small-sized biomacromolecule. Potential uses of this nanocontainer and of water-soluble derivatives are in drug delivery, wastewater detoxification, separation technology and as molecular reactor for controlled oligomerizations. Typically, the four-step synthesis of the cavitand building block and the subsequent multicomponent synthesis of the nanocontainer, including its purification, can be accomplished in about 4 weeks.

DISTAL Dibromoresorcin[4]arenes Through Selective Deactivation: A Practical Optimization

“…Thus, using NBS we achieved the twofold bromination in yields of > 99 % [R = (CH 2 ) 2 C 6 H 5 , 7a] and 95 % (R = C 5 H 11 , 7b), well above the 90 % for the fourfold bromination in the classical route to target compound 3. [10] We found a mild 1.5-fold excess of NBS per vacant aromatic upper-rim position is sufficient for the reaction, thereby minimizing the amount of unconverted reagent, which was easily removed by washing the solid raw product. The resulting crude product was sufficiently pure, since no by-products e.g.…”

“…The final products' overall yields are thus corrected to 57 % (3a) and 48 % (3b), as Table 1 displays. Further methods to increase conversion like pressure tube reactions, [17] or further increase of the reaction time [10] were not considered, in favor of a reliable and upscalable protocol. a (Phenetyl) 78 39 (84) [b] 99.5 93 94 26 (57) [b] b (Pentyl) 99 26 (70) [b] 95 86 84 18 (48) [b] [a] Total yield over 5 steps.…”

“…An overall yield between 36-55 % over four steps can be calculated. [10] While route A depends on a statistical yield distribution in the product-determining step and is, therefore, neither selective to the number of introduced substituents nor to the predominant isomer with respect to the desired twofold functionalization, route B presents a procedure with a directing factor. After the first lithiation at one of the four equivalent positions, the second lithium-halogen exchange is electrostatically repelled from the statistically more probable adjacent positions to the opposing one.…”

Multicomponent Assembly of Cavitand‐Based Polyacylhydrazone Nanocapsules

“…[27] For the synthesis of the extended cavitand 8, we applied a Suzuki-Miyaura coupling. Palladium-catalyzed cavitandaryl couplings had earlier been achieved using tetraiodocavitand 18 and arylboronic acids, [9l,p, 11n, 35] but required large excess of the boronic acids and almost stoichiometric amounts of palladium.…”

Designed Synthesis of a Highly Conjugated Hexaethynylbenzene‐Based Host for Supramolecular Architectures

“…Encapsulation within the inner space16–19 of a molecular container can accelerate reactions,20–23 alter the course of reactions in limited quarters,24–27 perturb equilibriums,28, 29 contort conformations,30 and stabilize either reactive reagents31 or reaction intermediates 32. The construction of efficient synthetic functional receptors with tunable cavities,33 and the self‐organization of guest molecules within these cavities through noncovalent interactions34 are challenging and require precise control over the topological and electronic properties of the interacting species.…”