Rhodium‐Catalyzed Enantioposition‐Selective Hydroarylation of Divinylphosphine Oxides with Aryl Boroxines

The rhodium‐catalyzed hydroarylation of divinylphosphine oxides (RP(O)(CH=CH₂)₂) with aryl boroxines ((ArBO)₃) gives the corresponding monoarylation products (RP(O)(CH=CHAr)CH₂CH₃) in high yields. One of the two vinyl groups in the phosphine oxide undergoes oxidative arylation while the other one is reduced to an ethyl moiety. These reactions proceed with high selectivity in terms of the enantiotopic vinyl groups in the presence of (R)‐DTBM‐segphos/Rh to give the P‐stereogenic monoarylation products with high enantioselectivity.     

Optimization of a special case of continuous-time Markov decision processes with compact action set

Performance optimization is considered for average-cost multichain Markov decision processes (MDPs) with compact action set. Since, for a general compact multichain model, the optimality equation system may have no solution, and also a policy iteration algorithm may yield a suboptimal policy rather than an optimal one, we concentrate only on a special case of multichain models in this paper, where we assume that the classifications of states are fixed identically rather than varying with policies. By using the concept of performance potentials, the existence of solutions to the optimality equation system is established, and then a potential-based policy iteration algorithm is supposed to solve this system. In addition, the optimality convergence, for recurrent classes, of the algorithm has been proved. Finally, a numerical example is provided.     

Ruthenium-catalyzed reaction of alkenyl triflates with zinc thiolates

A ruthenium complex coordinated with 3,4,7,8-tetramethyl-1,10-phenanthroline catalyzed the reaction of alkenyl triflates with zinc dithiolates to give alkenyl sulfides.     

Palladium-catalyzed desymmetrization of silacyclobutanes with alkynes: enantioselective synthesis of silicon-stereogenic 1-sila-2-cyclohexenes and mechanistic considerations

A palladium-catalyzed enantioselective desymmetrization of silacyclobutanes with alkynes has been developed to give silicon-stereogenic 1-sila-2-cyclohexenes with high enantioselectivity. The products thus obtained undergo further derivatizations with complete stereoselectivity, and a new catalytic cycle involving alkyne coordination (oxidative cyclization)-transmetalation (σ-bond metathesis)-reductive elimination has also been proposed.     

Rhodium-catalyzed asymmetric hydroarylation of diphenylphosphinylallenes with arylboronic acids

Rhodium-catalyzed asymmetric hydroarylation of diphenylphosphinylallenes with arylboronic acids proceeded in high yields with high regio- and enantioselectivity to give chiral allylphosphine oxides of up to 98% ee. The structural determination of the key intermediate, a pi-allylrhodium complex, was successful to establish the catalytic cycle of the reaction.     

Determination of peroxidase encapsulated in liposomes using homogentisic acid y-lactone chemiluminescence.

Homogentisic acid gamma-lactone (HAL) chemiluminescence (CL) was applied to the determination of horseradish peroxidase (HRP) encapsulated in liposomes. HRP was detected after the lysis of HRP-trapped liposomes with Triton X-100. CL response rate, detection limit and linear range of calibration curve for HRP in HAL CL were compared with those in piodophenol (p-IP)-enhanced luminol CL. Maximal light emission in HAL CL appeared more rapidly compared to that in p-IP enhanced luminol CL, thus resulting in remarkable reduction of CL measurement time. The detection limit for HRP in HAL CL was the same as that in p-IP-enhanced luminol CL. The linear range of calibration curve for HRP in HAL CL was improved by a factor of 50 compared with that in p-IP-enhanced luminol CL. From these results, it was found that HAL CL were superior to p-IP-enhanced luminol CL for the determination of HRP encapsulated in liposomes.