This second generation aromatic annulation is achieved by irradiation of a solution of acetylene and a vinyl or aryl ?-diazo ketone in dichloroethane.
22.
An annulation is defined as a transformation of one or more acyclic precursors resulting in the fusion of a new ring via two newly generated bonds.
23.
The original Wieland Miescher ketone is racemic and prepared in a Robinson annulation of 2-methyl-1, 3-cyclohexanedione and methyl vinyl ketone.
24.
Perhaps the most important step ( and the rate-determining step ) in the reaction mechanism is the annulation of the molecule via an electrocyclic ring closing.
25.
Albeit these reactions still required reaction temperatures above 300 �C they were able to make really useful products arising from the annulation of cyclopentene to a present ring system.
26.
Bildt refused to answer specifically whether that meant Serbian President Slobodan Milosevic, faced by a string of demonstrations over annulation of local elections, would have to step down.
27.
The Barbas group had reported the aldolase antibody catalyzed iminium-enamine Robinson annulation in their 1997 study that marked the beginning of their studies in the area now called organocatalysis.
28.
It was found that the cyclic portion of the synthesis proceeds through a Petkov transition-state model followed by an asymmetric [ 4 + 2 ] Robinson annulation into the desired diamide product.
29.
Examples are the Robinson annulation, Danheiser annulation and certain cycloadditions . "'Annular "'molecules are constructed from side-on condensed cyclic segments, for example helicenes and acenes.
30.
Examples are the Robinson annulation, Danheiser annulation and certain cycloadditions . "'Annular "'molecules are constructed from side-on condensed cyclic segments, for example helicenes and acenes.
