Rh(III)-Catalyzed One-Step Synthesis of ortho-Alkynylated Perylene Imide Dyes: Optical and Electrochemical Properties of New Derivatives.

A one-step Rh-catalyzed site-selective ortho-C-H alkynylation of perylene as well as naphthalene mono- and diimides is reported. A single step regioselective access to ortho-C-H alkynylated derivatives of these ryleneimides not only increases the step economy of the ortho-functionalization on these dyes but also provides a quick access route towards highly functionalized dyes that have potential optoelectronic applications. Increased solubility of tetra(triisopropylsilyl)acetylenyl PDIs in organic solvents greatly enhances their utility for further derivatization.

Cobalt(II)-catalyzed peri-C(sp2)-H selective hydroxylation of naphthalene monoimides.

Reported herein is an efficient and eco-friendly peri-selective monohydroxylation of naphthalene monoimides (NMIs) to access 4-hydroxy NMIs, which possess multidisciplinary applications. The key aspect of this method is the utilization of cobalt(II)-catalysis via a single electron transfer mechanism to achieve site-selective C(sp2)-hydroxylation. Transformation of the hydroxyl group into pseudohalides reveals its applications towards cross-coupling reactions.

Rh(III)-Catalyzed ortho-C-H Amidation of Naphthalene and Perylene Monoimides.

The direct formation of a C-N bond at the ortho-position of naphthalene monoimides (NMI) and perylene monoimides (PMI) is reported herein using dioxazolones as the amide source. This method affords direct access to ortho-amino NMI and PMI through an amidation and deprotection sequence. One-pot telescopic bay-bromination of ortho-amino PMIs was also achieved. The ortho-amidated NMIs and PMIs, accessed by the current methodology, show significant red shifts in their absorption and fluorescence spectra compared with the NMI and PMI alone. An improvement in the quantum yield and fluorescence lifetime was observed by the incorporation of pivalamide groups at the ortho-positions of NMI and PMI.

Ruthenium-Catalyzed C-H Functionalization of Benzoic Acids with Allyl Alcohols: A Controlled Reactivity Switch between C-H Alkenylation and C-H Alkylation Pathways.

A highly selective and switchable ruthenium-catalyzed ortho C-H alkylation and C-H alkenylation of benzoic acids with allyl alcohols is reported. A complete switch in selectivity is achieved upon tuning the reactivity of the organometallic intermediate in the carboxylate-directed C-H activation to provide access to highly useful motifs such as 2-alkylbenzoic acids and phthalides.