A dinuclear iminophosphorane palladacycle produces the missing link in the triphenylphosphane chalcogenide series of metallacycles.

In the world of science, in particular the section concerning the field of chemistry, when the results encountered during the experiment do not meet our expectations, our shrewdness may play an important role to open up new unexplored fields that could be much more interesting than what we were seeking. In those cases, our research undergoes an unforeseen shift, delivering novel and challenging results that may altogether alter our point of view and our future work. We have then struck serendipity. Specifically, in our investigation linked to palladacycles we have found that the new trends in their reactivity, as well as in their structure, have been, in many cases, related to this experience, broadening our research scope within this field. Herein, we describe our most relevant findings, which have shed new light upon the reactivity of palladacycles, thus opening new routes that lead to novel unexpected structures.

The direct metal-catalyzed C–H functionalization of arenes has emerged as a powerful tool for streamlining the synthesis of complex molecular scaffolds. However, despite the different chemical environments, the energy values of all C–H bonds are within a fairly narrow range; hence, the regioselective C–H bond functionalization poses a great challenge. The use of covalently bound directing groups is to date the most exploited approach to achieve regioselective C–H functionalization of arenes. However, the required installation and removal of those groups is a serious drawback. Recently, new strategies for regioselective metal-catalyzed distal C–H functionalization of arenes based on noncovalent forces (hydrogen bonds, Lewis acid–base interactions, ionic or electrostatic forces, etc.) have been developed to tackle these issues. Nowadays, these approaches have already showcased impressive advances. Therefore, the aim of this mini-review is to cover chronologically how these groundbreaking strategies evolved over the past decade.

A Ru-catalyzed isomerization of Achmatowicz derivatives that opens unexplored routes to diversify the biogenic furanic platform is reported. The mechanistic insights of this formally redox-neutral intramolecular process were studied computationally and by deuterium labeling. The transformation proved to be a robust synthetic tool to achieve the synthesis of bioderived-monomers and a series of 4-keto-δ-valerolactones that further enabled the development of a flexible strategy for the synthesis of acetogenins. A concise and protective group-free asymmetric total synthesis of two natural products, namely, (S,S)muricatacin and the (S,S)-L-factor, is also described.