Four- and Sixfold Tandem-Domino Reactions Leading to Dimeric Tetrasubstituted Alkenes Suitable as Molecular Switches
作者:Lutz F. Tietze、Bernd Waldecker、Dhandapani Ganapathy、Christoph Eichhorst、Thomas Lenzer、Kawon Oum、Sven O. Reichmann、Dietmar Stalke
DOI:10.1002/anie.201503538
日期:2015.8.24
A highly efficient palladium‐catalyzed fourfold tandem‐domino reaction consisting of two carbopalladation and two CH‐activation steps was developed for the synthesis of two types of tetrasubstitutedalkenes 3 and 6 with intrinsic helical chirality starting from substrates 1 and 4, respectively. A sixfold tandem‐domino reaction was also developed by including a Sonogashira reaction. 20 compounds with
Synthesis and Optical Properties of π-Conjugated Polymers Containing Fused Imidazole Skeleton
作者:Koji Takagi、Takuya Miwa、Hyuma Masu
DOI:10.1021/acs.macromol.6b01768
日期:2016.12.13
partner were found to affect the opticalproperties in CHCl3 solution as a result of steric and electronic factors. The spectroscopic measurements in film revealed that the bulky trisiloxane group helps π-conjugated polymers to form the π-stacked structure upon thermal annealing. The proton doping experiment was also carried out to find out that the protonation of imidazole nitrogen results in the different
bis(dibromomethyl)benzenes and a bis(dibromomethyl)thiophene as precursors of aromatic dialdehydes by bromination of dimethyl-substituted arenes under various reaction conditions (yields up to 99%). Several new variants of this reaction, including the use of N-bromosuccinimide (NBS) and bromine, and various solvents to replace carbon tetrachloride, benzene and carbondisulfide, were also tested. In the optimised
Efficient annulation of vic-diborylalkenes and -arenes with vic-bromo(bromomethyl)arenes has been achieved, using Pd(PPh3)4 as a catalyst in the presence of Cs2CO3 and water in THF at 60 ËC, giving rise to the corresponding indene and fluorene derivatives in good to high yields.
Synthesis and conformational properties of 5,7-disubstituted [3.3] Metacyclo (2,5) thiophenophane-1,12-diones
作者:Yuji Miyahara、Takahiko Inazu、Tamotsu Yoshino
DOI:10.1016/s0040-4039(00)99899-x
日期:1984.1
The title compounds showed unique conformational equilibria which were dependent upon the substituents in the 5,7-positions, the predominant conformers being in a O,S,O-, conformation with a highly deformed thiophene-2,5-dicarbonyl moiety.