The Indenyl Effect: Accelerated C-H Amidation of Arenes via Ind*Rh(III) Nitrene Transfer Catalysis

Phosphonium-substituted Diphosphaindenylide (PPI): Exploration of Biradical Character and Ligand Properties

Starting from C6 H4 (PCl2 )2 and the TMS-substituted ylide (TMS)2 C=PR3 (TMS=trimethylsilyl, R=p-tolyl), the phosphonium-substituted diphosphaindenylide PPI was prepared in two steps. CASSCF calculations as well as the reactivity toward diphenyl acetylene suggest a notable biradical character in PPI. Reaction with [Cr(CO)3 (MeCN)3 ] affords the complex [Cr(CO)3 (η5 -PPI)] (5). This complex was employed to explore the ligand properties of PPI, which demonstrates considerable potential through the combination of strong metal-ligand interactions and the possibility of a pronounced indenyl effect.

Cyclopentadienyl capped thorium(IV) porphyrinoid complex

The reaction between Th(IV) dipyriamethyrin dichloride and sodium cyclopentadienyl (Cp) results in the formation of a cyclopentadienyl capped thorium dipyriamethyrin complex, which to our knowledge represents the first expanded porphyrin f-element Cp complex.

Planar Chiral Rhodium Complex Based on the Tetrahydrofluorenyl Core for Enantioselective Catalysis

A simple four-step route to a chiral tetrahydrofluorenyl rhodium catalyst from naturally occurring (-)-α-pinene was developed. Our approach does not use multistep and time-consuming procedures such as chiral HPLC or diastereomeric resolution. The key to success lies in the face-selective coordination of rhodium to the sterically hindered tetrahydrofluorenyl ligand, giving only one diastereomeric complex. This catalyst proved to be highly efficient for asymmetric C-H annulation of aryl hydroxamates with alkenes (yield up to 95%, 91% ee) at low loading (up to 0.4 mol % based on Rh).

Acylsilanes in Transition-Metal-Catalyzed and Photochemical Reactions: Clarifying Product Formation

Acylsilanes are able to react as nucleophilic carbene precursors, electrophiles, and directing groups in C-H functionalization. To date, some of the products reportedly formed during transition-metal-catalyzed and photochemical reactions involving acylsilanes have been incorrectly assigned. To provide clarity, we herein address these structural misassignments and detail the revised structures. New insights into the reactivity of acylsilanes were also afforded via the discovery that light-induced siloxy carbenes participate in intramolecular 1,2-carbonyl addition to proximal esters.