The oxidative addition products trans-[Pd(NHC)(2)(Ar)Cl] (NHC = cyclo-C[N(t)BuCH](2); Ar = Me-4-C(6)H(4), MeO-4-C(6)H(4), CO(2)Me-4-C(6)H(4)) have been isolated in good yields from the reactions of ArCl with the amination precatalyst [Pd(NHC)(2)] and structurally characterized. The former undergo reversible dissociation of one NHC ligand at elevated temperatures, and a value of 25.57 kcal mol(-1) has been determined for the Pd-NHC dissociation enthalpy in the case where Ar = Me-4-C(6)H(4). Detailed kinetic studies have established that the oxidative addition reactions proceed by a dissociative mechanism. Rate data for the oxidation addition of Me-4-C(6)H(4)Cl to [Pd(NHC)(2)] compared to that obtained for the [Pd(NHC)(2)]-catalyzed coupling of morpholine with 4-chlorotoluene are consistent with a rate-determining oxidative addition in the catalytic amination reaction. The relative rates of oxidative addition of the three aryl chlorides to [Pd(NHC)(2)] (CO(2)Me-4-C(6)H(4)Cl > Me-4-C(6)H(4)Cl > MeO-4-C(6)H(4)Cl) reflect the electronic nature of the substituents and also parallel observed trends in coupling efficiency for these aryl halides in aminations.

The development of a highly compact and powerful reactor for synthetic organic photochemistry is described enabling a 10-fold reduction in reaction times, with up to 30% more power efficiency than previous fluorinated ethylene propylene tube reactors. Two reactions gave over 1 kg of product in 24 h. Two other reactions had productivities of 4 and 8 kg in 24 h. The reactor consists of a succession of quartz tubes connected together in series and arranged axially around a variable power mercury lamp. This compact and relatively simple device can be safely operated in a standard fumehood.

RECEIVED DATE (to be automatically inserted after your manuscript is accepted if requiredaccording to the journal that you are submitting your paper to) 2 TOC AbstractCommercial reagents and literature conditions used to evaluate "Borrowing hydrogen" methodology for pharmaceutical intermediates. Yields are high for simple R/R', but challenges identified for typical pharma substrates. 3 AbstractThe use of the "borrowing hydrogen strategy" in the synthesis of a number of typical pharmaceutical intermediates has been investigated. The main aim of this work was to investigate the scope and limitations of current methodology using standard laboratory techniques in an industrial context. Some interesting and significant results were achieved across a diverse set of complex substrates; however several drawbacks with this approach were identified, such as the high loading, poor turnover and susceptibility to substrate inactivation of the catalysts. These are areas which are highlighted for future investigation and improvements.

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