Dedicated to Prof. Janine Cossy in recognition of her important contributions to the discovery of new stereoselective methods and their application to the synthesis of natural productsWe describe herein a high yielding and metal-free methodology to access 9-aminophenanthrene derivatives and heterocyclic analogues starting from biaryl acetamides. The conversion of the substrates to their corresponding keteniminium salts triggers a spontaneous electrocyclization occurring at room temperature within a few minutes. DFT Calculations and competition reactions were carried out to rationalize the observed reactivity and understand the relative kinetics compared to other known reactions involving keteniminium salts.

A methodology allowing the direct preparation of β-amino-α,α-difluoroketones from the Ruppert–Prakash reagent (CF3TMS), acyltrimethylsilanes and N-Boc or N-(diphenylphosphinyl)imines is reported. The process, initiated by a catalytic amount of tetra-n-butylammonium difluorotriphenylsilicate (TBAT), involves the addition of CF3TMS to the acylsilane, followed by a Brook rearrangement and elimination of a fluoride anion. The latter promotes the addition of the resulting difluoroenoxysilane to the imine. The higher electrophilicity of the acylsilane compared to the imine allows the direct mixing of all the reagents in a three-component, one-pot process.

Unactivated alkenyl iodides and bromides underwent an unprecedented palladium-catalyzed relay-Heck cross-coupling with a whole range of alkenols of different chain lengths linking the alkene and the alcohol, affording unsaturated aldehydes and ketones in moderate to good yields. In contrast, alkenyl triflates were not suitable partners for this reaction. This method allowed the preparation of open-chain analogues of the musk odorant Vulcanolide, several of which retained key olfactory properties of the parent molecule.

Polycyclic aromatic hydrocarbons (PAHs) are an important family of molecules in science and technology. Amino‐substituted PAHs are promising building blocks to create attractive molecules for materials science. However, the synthetic limitations have hampered to produce diverse structures of amino‐substituted PAHs. Here we describe a novel efficient synthetic method to access amino‐substituted PAHs through the electrocyclization of highly reactive keteniminium species. We demonstrated the synthesis of various amino‐substituted PAHs and disclosed some of their photophysical properties. Furthermore, combination with theoretical calculation revealed that the multiple electrocyclization reactions of keteniminium species is a stepwise process and the fusion of additional aromatic ring to the substrate accelerates the electrocyclization.