32337-65-8

Upstream product

• 42381-05-5 2-amino-2-adamantanecarboxylic acid 
• 85-44-9 phthalic anhydride 

Relevant academic research and scientific papers

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin

Stability constants for the inclusion complexes of cyclohexylphthalimide 2 and adamantylphthalimide 3 with β-cyclodextrin (β-CD) were determined by 1H NMR titration, K = 190 ± 50 M?1, and K = 2600 ± 600 M?1, respectively. Photochemical reactivity of the inclusion complexes 2&at;β-CD and 3&at;β-CD was investigated, and we found out that β-CD does not affect the decarboxylation efficiency, while it affects the subsequent photochemical H-abstraction, resulting in different product distribution upon irradiation in the presence of β-CD. The formation of ternary complexes with acrylonitrile (AN) and 2&at;β-CD or 3&at;β-CD was also essayed by 1H NMR. Although the formation of such complexes was suggested, stability constants could not be determined. Irradiation of 2&at;β-CD in the presence of AN in aqueous solution where cycloadduct 7 was formed highly suggests that decarboxylation and [3 + 2] cycloaddition take place in the ternary complex, whereas such a reactivity from bulky adamantane 3 is less likely. This proof of principle that decarboxylation and cycloaddition can be performed in the β-CD cavity has a significant importance for the design of new supramolecular systems for the control of photoreactivity.

Photodecarboxylation of Adamantane Amino Acids Activated by Phthalimide

Adamantane α-, β-, and δ-amino acids activated by phthalimide (i.e., 3–6) were synthesized, and their photochemical reactivities were investigated. Amino acid derivatives 3–6 underwent a photoinduced electron transfer (PET) and decarboxylation reaction sequence, most probably through a triplet excited state. The decarboxylations of the β-amino acid derivatives were succeeded by cyclization reactions that afforded complex polycyclic molecules with potential biological interest. The adamantyl radical that is produced by the photoinduced decarboxylation could be trapped by alkenes or oxygen to deliver adducts or alcohols, respectively. The photodecarboxylation process was shown to be more efficient under acetone sensitization conditions (with quantum yields, Φ = 0.02–0.5) than upon direct excitation, and the reactivity was dependent on the chain length (intramolecular distance) between the electron donor (carboxylate) and acceptor (phthalimide in the triplet excited state) of the derivative. The formation of different radicals, that is, the 1- or 2-adamantyl intermediate, probably does not affect the overall rate of the decarboxylation This current report provides a better understanding of photodecarboxylation and the rational design of molecular systems to undergo photoinduced decarboxylation and cyclization reactions.