Aromatic aldols and 1,5-diketones as optimized fragrance photocages.

Aromatic aldols and 1,5-diketones with abstractable γ-hydrogen atoms are highly photoactive cage molecules for the release of fragrance carbonyl compounds (aldehydes and Michael ketones, respectively). Aldols 3a-d are easily accessible by Mukaiyama addition and are cleaved to form the substrates with high quantum yields under solar radiation. By tuning the properties of the chromophores, a series of δ-damascone cages 5 were developed that can be used for selective and fast (5a,e) or slow (5b,d) release of fragrances under air and solar irradiation. The intermediates of the Norrish II process were observed by laser transient absorption spectroscopy.

Synthetic Studies on Palau'amine. Construction of the Cyclopentane Core via an Asymmetric 1,3-Dipolar Cycloaddition.

The cyclopentane core of palau'amine has been constructed in optically pure form through the use of an asymmetric azomethine ylid [1,3]-dipolar cycloaddition reaction.

Synthesis of 9-N-cinchona alkaloid peptide hybrid derivatives: preparation and conformational study of 9-N-acylamino(9-deoxy)cinchona alkaloids.

The synthesis and conformational analyses of several 9-N-acylamino(9-deoxy)cinchona alkaloids is presented. Peptides were connected to cinchona alkaloids via a 9-amino group. The synthesis of the new cinchona alkaloid derivatives was performed straightforwardly from 9-amino(9-deoxy)dihydroquinidine via coupling with carboxylic acid chlorides and several dipeptides. Both alkaloid derivatives with the configuration of the corresponding natural product as well as its unnatural epimer were studied. The conformations of the prepared derivatives in solution were determined by NMR spectroscopy. It is shown that the conformation is strongly influenced by the configuration at the 9-position.