The self-condensation of alkynals was for the first time implemented under mild organocatalytic conditions and was successfully linked with a domino organocatalytic inverse-electron-demand oxa-Diels-Alder reaction, which led to the development of a facile one-pot method to produce a wide variety of polysubstituted chiral 3,4-dihydropyrans with good to high yields and diastereoselectivities and ...

N-Vinylpirrolidinone reacts with (E)-ethyl 5-hydroxy-3-(4-oxo-4H-chromen-3-yl) acrylate (1) through a domino reaction similar to that reported reaction for ethyl vinyl ether. Inverse electron demand Diels–Alder (IEDDA)–elimination-IEDDA generates isomeric tetracycles 5 and 6. The assignment of the relative stereochemistry of the products was made by comparing the proton couplings with those obt...

Recursive modelling for the kinematics and dynamics of the known 3-PRR planar parallel robot is established in this paper. Three identical planar legs connecting to the moving platform are located in a vertical plane. Knowing themotion of the platform,we develop first the inverse kinematics and determine the positions, velocities and accelerations of the robot. Further, the principle of virtual...

Carbohydrate microarrays are an emerging tool for the high-throughput screening of carbohydrate-protein interactions that represent the basis of many biologically and medicinally relevant processes. The crucial step in the preparation of carbohydrate arrays is the attachment of carbohydrate probes to the surface. We examined the Diels-Alder reaction with inverse-electron-demand (DARinv) as an i...

Bio-orthogonal labelling schemes based on inverse-electron-demand Diels-Alder (IEDDA) cycloaddition have attracted much attention in chemical biology recently. The appealing features of this reaction, such as the fast reaction kinetics, fully bio-orthogonal nature and high selectivity, have helped chemical biologists gain deeper understanding of biochemical processes at the molecular level. Lis...

Strain-promoted azide-alkyne cycloaddition (SPAAC) as a conjugation tool has found broad application in material sciences, chemical biology and even in vivo use. However, despite tremendous effort, SPAAC remains fairly slow (0.2-0.5 M(-1) s(-1)) and efforts to increase reaction rates by tailoring of cyclooctyne structure have suffered from a poor trade-off between cyclooctyne reactivity and sta...

This document gives a short introduction into Spatial Equilibrium modeling with GAMS. 1. Intertemporal-Spatial Price Equilibrium Solving spatial equilibrium models by mathematical programming is pioneered by [9],[12], [11], and [13]. One of the most basic forms is the transportation problem, also known as the “Koopmans-Hitchcock” model. An example is found in the GAMS model library in trnsport....

In the last few years we demonstrated the utility of the phthalimidesulfenyl chloride (PhthNSCl, Phth = Phthaloyl) mediated generation of α,α’-dioxothiones and several related thiocarbonyl species. These reactive thione derivatives can be used as efficient electron-poor dienes in inverse electron demand Diels-Alder reactions with a plethora of electron rich alkenes, giving rise to interesting s...

Estimates for the U.S. suggest that at least in some sectors productivity enhancing reallocation is the dominant factor in accounting for productivity growth. An open question, particularly relevant for developing countries, is whether reallocation is always productivity enhancing. It may be that imperfect competition or other barriers to competitive environments imply that the reallocation pro...