Diels-Alder approach to tetralin-based constrained alpha-amino acid derivatives

Molecular Acrobatics in Polycyclic Frames: Synthesis of "Kurmanediol" via Post-synthetic Modification of Cage Molecules by Olefinic Metathesis

We report late-stage ring-opening metathesis (ROM), ring-rearrangement metathesis (RRM), and ring-closing metathesis (RCM) approaches to generate expanded pentacycloundecane (PCUD) cage derivatives. These higher-order intricate polycyclic cage systems are aesthetically pleasing and structurally intriguing. Their assembly maintains molecular symmetry during the entire synthetic sequence. To this end, metathesis-based catalysts are used to execute the ROM, RRM, and RCM strategies. The synthetic approach to these cage polycycles involves the Diels-Alder reaction, [2 + 2] photocycloaddition, RRM, ROM, and RCM as key steps.

Design, Synthesis and Late-Stage Modification of Indane-Based Peptides via [2+2+2] Cyclotrimerization

Here, we prepared several dipeptides containing 2-aminoindane-2-carboxylic acid (Aic) and carried out further synthetic transformations. Synthesis and purification of modified peptides by using [2+2+2] cyclotrimerization is a challenging task. We are able to modify the unusual amino acids and peptide derivatives by late-stage incorporation of benzylhalo functionality. To incorporate benzylhalo moiety we used [2+2+2] cyclotrimerization in the presence of Mo(CO)₆ . These halo derivatives are potential substrates for further modification by Sonogashira reaction, Suzuki-Miyaura cross-coupling, sultine formation, and the Diels-Alder reaction sequence.

A diversity-oriented approach to indolocarbazoles via Fischer indolization and olefin metathesis: total synthesis of tjipanazole D and I

New synthetic strategies to indolocarbazoles have been reported via two-fold Fischer indolization under green conditions using l-(+)-tartaric acid and N,N-dimethyl urea.

Diversity-Oriented Approaches to Polycyclics and Bioinspired Molecules via the Diels-Alder Strategy: Green Chemistry, Synthetic Economy, and Beyond

We describe diverse approaches to various dienes and their utilization in the Diels-Alder reaction to produce a variety of polycycles. The dienes covered here are prepared by simple alkylation reaction or via the Claisen rearrangement or by enyne metathesis of alkyne or enyne building blocks. Here, we have also included the Diels-Alder chemistry of dendralenes, a higher analog of cross-conjugated dienes. The present article is inclusive of o-xylylene derivatives that are generated in situ starting with benzosultine or benzosulfone derivatives. The Diels-Alder reaction of these dienes with various dienophiles gave diverse polycyclic systems and biologically important targets.

Rational design of dynamic ammonium salt catalysts towards more flexible and selective function

This review focuses on the development of dynamic ammonium salt catalysis for selective organic transformations conducted in our laboratory since 2002. Several important concepts in designing of catalysts are described with some examples. In particular, the practical synthesis of chiral 1,1'-binaphthyl-2,2'-disulfonic acid (BINSA) and its application in chiral ammonium salt catalysis for the enantioselective direct Mannich-type reaction are described.

Application of the Suzuki-Miyaura cross-coupling reaction for the modification of phenylalanine peptides

We have demonstrated an exceptionally simple and a useful methodology for modification of unusual phenylalanine peptides by adapting the building block approach using the Suzuki-Miyaura cross-coupling reaction as a key step. This strategy gave a good overall yield of various modified tri- and pentapeptides that may be useful to prepare various biologically active peptides in a short period of time.

A new approach for modification of phenylalanine peptides by Suzuki-Miyaura coupling reaction

For the first time, we have modified phenylalanine peptides by the Suzuki-Miyaura coupling reaction which may be useful in developing combinatorial libraries of peptidomimetics.