A C₃‐Symmetric Palladium Catalyst with a Phosphorus‐Based Tripodal Ligand

Chirality in the Absence of Rigid Stereogenic Elements: The Design of Configurationally Stable C3‐Symmetric Propellers

“…[3] We considered that, at least in principle, chiral and configurationally stable trisA C H T U N G T R E N N U N G (aryl)phosphanes could be obtained as residual enantiomers as long as their structural architecture could satisfy the conditions required for the existence of residual stereoisomerism, a phenomenon discovered by Prof. K. Mislow in the 1970s. [4] Residual stereoisomers "result whenever closed subsets of appropriately substituted interconverting isomers are generated from a full set under the operation of a given stereomerization" mechanism.…”

An Unprecedented Iridium(III) Catalyst for Stereoselective Dimerisation of Terminal Alkynes

“…The presence of three non-equivalent phosphorus atoms in a pseudo T-shaped arrangement can be assumed from its 3 ], where they are 2.509 and 3.092 , respectively. [7] Furthermore, the C À C bond distances along the C 4 Since the b-hydrogen elimination from 3 could give rise to highly unsaturated four-carbon derivatives, which are nowadays compounds of great relevance, [8] the capacity of 3 to undergo b-hydrogen elimination was investigated: i) no decomposition occurs even after 3 days in refluxing CHCl 3 or MeOH, but ii) 3 readily reacts with stoichiometric amounts of pyridine in refluxing MeOH, releasing the butadienyl moiety as (E)-1,4-diphenylbut-1-en-3-yne and yielding the hexacoordinated complex 4 (Scheme 1, reaction i). In addition, 4 converts to 3 when reacted with phenylacetylene (PhC CH/Ir = 2/1 molar ratio).…”

“…In this context, here we report the synthesis of the (1), starting from the P-tripodal ligand HTIMP 3 , [4] and its deriva-…”

“…[5] To obtain a more reactive complex, a methanol solution of 1 was treated with AgBF 4 at room temperature for 12 h. Under these conditions the chloride group from 1 was efficiently abstracted and the resulting product was assigned the structure Cationic complex 2 does react with phenylacetylene in methanol and quantitavely gives rise to a new compound, identified as the butadienyl species 3 (Scheme 1, reaction i). [6] The 19 F NMR spectrum of 3 shows a singlet at À154.6 ppm, indicating an uncoordinated BF 4 À anion. The presence of three non-equivalent phosphorus atoms in a pseudo T-shaped arrangement can be assumed from its 3 ], where they are 2.509 and 3.092 , respectively.…”

Chelation‐Driven Rearrangement of Primary Alkyl Aminopalladation Products to Stable Trisubstituted Alkyl–Palladium Complexes

“…[11] Only a few examples of nonstabilized trisubstituted alkyl-palladium complexes have been reported. [12] Furthermore,systems that allow the formation and control over the interconversion of two differentially substituted alkyl-metal complexes are even more rare. Here we describe a finely balanced system in which the rearrangement between a primary alkyl complex and a trisubstituted alkyl complex can be controlled by the choice of substrate and the reaction conditions.…”