Intramolecular thermal stepwise [2 + 2] cycloadditions: investigation of a stereoselective synthesis of [n.2.0]-bicyclolactones

YesFused cyclobutanes are found in a range of natural products and formation of these motifs in a straightforward and easy manner represents an interesting synthetic challenge. To this end we investigated an intramolecular variant of the thermal enamine [2 + 2] cyclisation, developing a diastereoselective intramolecular enamine [2 + 2] cyclisation furnishing δ lactone and lactam fused cyclobutenes in good yield and excellent diastereoselectivity.The work was funded by Yorkshire Cancer Researc

Synthesis of fused indoline-cyclobutanone derivatives via an intramolecular [2+2] cycloaddition

We thank the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT, grant code EP/L016419/1, R.M.N.) for funding. We thank the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013) ERC grant agreement no. 279850 (A.D.S.). A.D.S. thanks the Royal Society for a Wolfson Research Merit Award. We also thank the EPSRC UK National Mass Spectrometry Service at Swansea. The research data supporting this publication can be accessed at https://doi.org/10.17630/00aff760-0732-438f-a9d1-30c7cf3a87a0A serendipitously-discovered process for the synthesis of heterocyclic products containing a novel fused indoline-cyclobutanone ring system is reported. This process is believed to take place through in situ generation of a ketene intermediate, followed by intramolecular [2+2] cycloaddition with a pendant enamide. The formation of a ketene intermediate in this process is significant as the reaction conditions employed are analogous to those commonly used in tertiary amine Lewis base catalysis, where the potential intermediacy of ketenes is an important consideration that is often overlooked.PostprintPeer reviewe

Antitumor Peptides from Marine Organisms

The biodiversity of the marine environment and the associated chemical diversity constitute a practically unlimited resource of new antitumor agents in the field of the development of marine bioactive substances. In this review, the progress on studies of antitumor peptides from marine sources is provided. The biological properties and mechanisms of action of different marine peptides are described; information about their molecular diversity is also presented. Novel peptides that induce apoptosis signal pathway, affect the tubulin-microtubule equilibrium and inhibit angiogenesis are presented in association with their pharmacological properties. It is intended to provide useful information for further research in the fields of marine antitumor peptides