Synthesis Of Novel Chiral Spirocycle Acetal (Ketal) Compounds

With the development of society and progress in exploring the nature, the interdisciplinary research has been the rising scientific mainstream. Supramolecular chemistry and dendrimer polymer are the Frontier subjects, which are the integration of modern chemistry, material science and life science. Their growth are relative with not only themselves (crown ether, cyclodextrin, calixarene and C60 etc) but also molecule self-assemble (bimolecular membranes, miscells and DNA double helixes, et al.), molecule -based devices and novel organic materials.Recently, Asymmetric reaction attracts much attention, and becomes the center of organic synthesis because of the advantages of transition metal complex chelated with chiral spirocycles, such as better stereo selectivity and chemo-selectivity, et al. Therefore, C2 symmetric axis is an important factor when the chiral ligand is designed. In addition, spirocycle axially compound is a prominent role in supramolecular chemistry and dendrimer polymer.We thank the National Nature Science Foundation of China (20472064) for financial support of this investigation. A series of compounds were synthesized, and the original results could be helpful for further study in the field. The main achievements are as follows.1) Simple spirocycle compound, 3, 9-diphenyl-2, 4, 8, 10-tetraoxospiro [5.5] undecane, was synthesized by acetalation between benzenealdehyde and pentaerythritol at the presence of acid at room temperature. The racemates were separated into R and S enantiomers.2) Spirocycle arborol including 18 hydroxyl end-groups was designed and synthesized with facile procedures and inexpensive chemicals through the stepwise reactions and 1, 3, 5- triacetylbenzene as the core.3) Based on Zhang's work, the 2nd generation six-membered spirocycle arborol including 12 hydroxyl end-groups was designed and synthesized by double exponential growth strategy at the presence of I2 catalyst.4) The multi-carbonyl intermediates were prepared with high yields by nucleophilic substitution and dehydration reaction in organic solution. By dilution method, ketalation between them with pentaerythritol gave the corresponding macrocycle ketals at the presence of TsOH catalyst. The syntheses of them were improved under microwave irradiation. The results showed that they had many advantages, such as less reaction time, fewer side reactions, and higher yields.5) Macrocycle isomeric compounds including multi-spirocycle unites were synthesized by template polymerization and dilution method at the presence of TsOH catalyst. All products and intermediates were confirmed by HPLC,IR,~1H NMR,MS and EA, especially spirocycle compound, 3, 9-diphenyl-2, 4, 8, 10-tetraoxospiro [5.5] undecane, was resolved.