Transformation of Imine Cages into Hydrocarbon Cages

Abstract

In contrast to organic cages which are formed by exploiting dynamic covalent chemistry, such as boronic ester cages, imine cages, or disulfide cages, those with a fully carbonaceous backbone are rarer. With the exception of alkyne metathesis based approaches, the vast majority of hydrocarbon cages need to be synthesized by kinetically controlled bond formation. This strategy implies a multiple step synthesis and no correction mechanism in the final macrocyclization step, both of which are responsible for low overall yields. Whereas for smaller cages the intrinsic drawbacks are not always obvious, larger cages are seldom synthesized in yields beyond a few tenths of a percent. Presented herein is a three‐step method to convert imine cages into hydrocarbon cages. The method has been successfully applied to even larger structures such as derivatives of C 72 H 72 , an unknown cage suggested by Fritz Vögtle more than 20 years ago.

Inducing Social Self‐Sorting in Organic Cages To Tune The Shape of The Internal Cavity

“…[10][11][12][13][14] Furthermore,cages offer synthetic handles that can be used to finely tune their cavity shape and electronic properties,a nd hence potential interactions with guest molecules. [7,[15][16][17][18][19] However, the synthesis of molecular cages is often challenging,p articularly where multiple bonds must be formed selectively.T oavoid this problem, many molecular cage syntheses take advantage of dynamic covalent chemistry, in which reversible reactions provide an error correction mechanism to ensure the thermodynamic cage product is obtained. [20][21][22] In the case of imine-based cages,m ultiple amines and aldehydes must react to yield asingle cage species instead of oligomeric mixtures of imines.…”

Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks

“…10B). 81 This widespread pre-orientation strategy is dependent on four prerequisites (Fig. 11): The reversible assembly does not disassemble under the conditions of the stability inducing step; the building blocks are oriented correctly to allow the reaction to occur; the order in the material needs to withstand forces generated during or because of the transformation; the reagents and catalysts need to reach the COF linkage and need to be able to perform the reaction irrespective of the sterically challenging environment.…”

The Chemistry of Porous Organic Molecular Materials

“…[263] Mastalerz et al reported that an imine-based POC could be chemically transformed into hydrocarbon cage, using a three-step method: imine reduction, nitrosylation with isoamyl nitrite, and Overberger rearrangement. [264] Using different chemistry, Yamago et al reported a carbon-based nanocage, which was prepared by postsynthetically modifying a platinum nanocage, via reductive elimination of the platinum (Figure 11). [228] Itami et al, and others, have reported a series of carbon-based nanocages, which were prepared by postsynthetically aromatizing cyclohexane moieties under acidic conditions, [225,226,265] and related reductive aromatization reactions.…”