Abstract: Method of forming a trisubstituted ethylene compound, the method comprising: (A) providing a trisubstituted ethylene compound bearing a first, a second and a third substituent, in which the first and the second substituent are bound to the one olefinic carbon atom and are different from one another; (B) providing a monosubstituted ethylene compound or a disubstituted ethylene compound in which the substituents are vicinally bound to the olefinic carbon atoms, bearing at least a fourth substituent, respectively; (C) subjecting the trisubstituted ethylene compound provided in step (A) to a cross-metathesis reaction with olefin provided in step (B) to form said trisubstituted ethylene, wherein the cross-metathesis reaction is catalysed by a transition metal complex bearing ligands from which one ligand is a carbene ligand, wherein the carbene complex is characterized by a M=C moiety, wherein M is the transition metal; and wherein the reaction proceeds stereoselectively.

Abstract: The present disclosure provides compounds, compositions, and methods for preparing alkenyl halides and/or haloalkyl-substituted olefins with Z-selectivity. The methods are particularly useful for preparing alkenyl fluorides such as CF3-substituted olefins by means of cross-metathesis reactions using halogen-containing molybdenum and tungsten complexes.

Abstract: Method of forming a trisubstituted ethylene compound, the method comprising: (A) providing a trisubstituted ethylene compound bearing a first, a second and a third substituent, in which the first and the second substituent are bound to the one olefinic carbon atom and are different from one another; (B) providing a monosubstituted ethylene compound or a disubstituted ethylene compound in which the substituents are vicinally bound to the olefinic carbon atoms, bearing at least a fourth substituent, respectively; (C) subjecting the trisubstituted ethylene compound provided in step (A) to a cross-metathesis reaction with olefin provided in step (B) to form said trisubstituted ethylene, wherein the cross-metathesis reaction is catalysed by a transition metal complex bearing ligands from which one ligand is a carbene ligand, wherein the carbene complex is characterized by a M?C moiety, wherein M is the transition metal; and wherein the reaction proceeds stereoselectively.

Abstract: The present disclosure provides compounds, compositions, and methods for preparing alkenyl halides and/or haloalkyl-substituted olefins with Z-selectivity. The methods are particularly useful for preparing alkenyl fluorides such as CF3-substituted olefins by means of cross-metathesis reactions using halogen-containing molybdenum and tungsten complexes.

Abstract: A transmission line speaker enclosure featuring a main enclosure, a speaker driver and an exit port in the main enclosure, exit port walls extend from the exit port into the main enclosure; and an inner sub enclosure in the main enclosure having a curved vertex facing the speaker driver and walls extending from ends of the vertex, the vertex has an angle between about 40 to 80 degrees, the vertex is either attached or separated from the magnet of the speaker driver by a gap, the vertex functions to divert sounds exiting the speaker driver between walls of the inner sub enclosure wall the main enclosure, then between the walls of the inner sub enclosure and the exit port and further out of the exit port, wherein back waves generated by the speaker driver can have total travelling distance of about ¼ wavelength of a tuned frequency.