Abstract:We have developed a one-pot ring-closing metathesis (RCM)/oxidation methodology to yield various 2-quinolines from 2-vinyl-N-allylaniline derivatives. This is a first example of an oxidation involving methylene (CH 2 ) groups with modified Grubbs-type ruthenium complexes. Hence, this adds an example of a non-methathesis reaction using a ruthenium carbene catalyst.

We have found in the SR-HXPS measurement of Piranha-treated Au(111)/mica that the gold surface underwent sulfur modification during this treatment, which was believed to have only removed impurities from the gold surface. We also successfully developed a practical Pd material, SAPd, whose Pd was immobilized on sulfur-modified Au. With the lowest Pd-releasing levels and high recyclability, this is one of the best Pd materials thus far developed. Because it leaches extremely low levels of Pd into reaction mixtures, removal of the residual Pd is unnecessary using SAPd, even in syntheses involving pharmaceutical ingredients.

An efficient method for the palladium-catalyzed amination of unprotected bromoimidazoles and bromopyrazoles is presented. The transformation is facilitated by the use of our newly developed Pd precatalyst based on the bulky biarylphosphine ligand tBuBrettPhos (L4). The mild reaction conditions employed allow for the preparation of a broad scope of aminoimidazoles and aminopyrazoles in moderate to excellent yields.

Pd(II)-catalyzed tertiary C(sp(3))-H arylation of cyclopropanes via directing group-mediated C-H activation for the construction of a chiral quaternary carbon center on cyclopropanes using aryl iodides as a coupling partner is reported. The arylation had a wide substrate scope and good functional group tolerance, including heteroaryl iodides, to provide various chiral arylcyclopropanes with the cis- and trans-1,1,2-trisubstituted structures.

A sulfur-modified gold-supported palladium material (SAPd) has been developed bearing palladium nanoparticles on its surface. Herein, we report for the first time the use of SAPd to affect a Pd-nanoparticle-catalyzed 1,7-Pd migration reaction for the synthesis of benzotriazoles via C-H bond activation. The resulting benzotriazoles were evaluated in terms of their inhibitory activity toward indoleamine 2,3-dioxygenase.

Abstract:The actual active species of the recently developed sulfur-modified, gold-supported palladium material, S-modified Au-supported Pd (SAPd), with one of the lowest Pd-releasing levels and high recyclability in the Suzuki-Miyaura coupling, was investigated. Also, SAPd was found to work repeatedly as an excellent Pd reservoir for liquid-phase combinatorial synthesis.

Improved processes for the preparation of biphenyl-based phosphine ligands t-BuBrettPhos, RockPhos, and BrettPhos are presented. The new methods, featuring the use of Grignard reagents and catalytic amounts of copper, are superior to the previous methods, which require the use of t-butyllithium and stoichiometric amounts of copper. Specifically, the use of less dangerous reagents provides a safer process, while the use of catalytic amounts of copper allows for the isolation of pure products in high yield. These improvements are particularly significant for the large scale preparation of these ligands.

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