α-Carbonyl Radical Cyclizatio n in Organic Synthesis

Intramolecular radical cyclization reactions are now used routinely to synthesize carbocyclic and heterocyclic structures. We have reported that α-carbonyl radicals 1, generated from the corresponding iodo ketones or enones, underwent intramolecular radical cyclization smoothly to afford products 2.1, 2,3     

α-Carbonyl Radical Cyclization for the Total Synthesis of Natural Products

Intramolecular radical cyclization reactions are now used routinely to synthesize carbocyclic and heterocyclicstructures. We have reported that α-carbonyl radicals 1, generated from the corresponding iodo ketones or enones,underwent intramolecular radical cyclization smoothly to afford products 2. [1,2]     

Robust D-stability analysis for linear discrete singular time-delay systems with structured and unstructured parameter uncertainties

In this paper, the robust D-stability problem (i.e. the robusteigenvalue-clustering in a specified circular region problem)of linear discrete singular time-delay systems with structured(elemental) and unstructured (norm-bounded) parameter uncertaintiesis investigated. Under the assumptions that the linear nominaldiscrete singular time-delay system is regular and impulse-free,and has all its finite eigenvalues lying inside a specifiedcircular region, a new sufficient condition is proposed to preservethe assumed properties when structured and unstructured parameteruncertainties are added into the linear nominal discrete singulartime-delay system. When all the finite eigenvalues are justrequired to locate inside the unit circle of the z-plane, theproposed criterion will become the stability robustness criterion.For the case that the linear discrete singular time-delay systemis only subject to structured parameter uncertainties, by anillustrative example, the presented sufficient condition isshown to be less conservative than the existing one reportedrecently in the literature.     

Regional eigenvalue-clustering robustness of linear output feedback systems with both time-varying structured and unstructured uncertainties as well as nonlinear actuators

This paper investigates the regional eigenvalue-clusteringrobustness of linear output feedback systems with both time-varyingstructured (elemental) and unstructured (norm-bounded) parameteruncertainties as well as nonlinear actuators. A sufficient conditionis proposed for ensuring that all the eigenvalues of outputfeedback systems with both time-varying structured and unstructuredparameter uncertainties as well as nonlinear actuators remaininside the specified region. No restriction is imposed on theshapes of the specified region. The proposed method is applicableto both the continuous-time case and the discrete-time case.When all the eigenvalues are just required to locate in thestable region, the proposed criterion will become the stabilityrobustness criterion. Two numerical examples are given to illustratethe application of the proposed sufficient condition.