Preparation and Properties of Cycloocta [1,2‐b: 4,3‐b′:5,6‐b″:8,7‐b‴] tetrathiophene

Abstract

fumarate (59.8g, 347 mmol) at room temperature. During the reaction the temperature of the mixture is kept at 35-4OT by water cooling. After stirring for 1 h, all the components that are volatile at 1 lS"C/O.l torr are distilled off to leave 2.1 g of a black viscous residue. Fractional distillation affords 42.7 g of 96 YO pure (GC) diethyl fumarate and 17.Sg of 93.8 % pure (GC) (Zb), b. p. 63-65"C/0.001 torr, which still contains diethyl fumarate (1.6%) and six other unknown compounds (4.6 %).Received: December 10, I973 [Z 2 b IE] German version: Angew. Chem. 86. 518 (1974) [ I ] P. Diazaborolines are derived from pyrroles by formal isosteric replacement of a C=C by a BN group and are isoelectronic with the cyclopentadienide ion. They therefore warrant attention as potential complex ligands. The first representative of this class, 1,3-dimethyl-2-phenyldiazaboroline~", has been described in a recent publication. We have now found a novel elegant preparation of these heterocycles in the synthesis of 1,3-diphenyl-2,4,S-trimethyl-1,3,2-diazaboroline ( 1 ). Reduction of the boronium salt ( 2 ) with sodium amalgam in diethyl ether affords (1) in about 50% yield.

Density functional theory and time‐dependent density functional theory studies on optoelectronic properties of fused heterocycles with cyclooctatetraene

“…There are reports in the literature on cyclooctatetrathiophene (COTh) where thiophene fused with the COT framework 17 . It is also reported that with the presence of electron‐rich thiophene on the boundary and having flexible π‐conjugated skeletons, COTh has prominent applications in optoelectronics 14,17–19 . Considering the connectivity of thiophene, COTh has 15 isomers, and four of them were synthesized and reported by Wang et al 17 The different connectivity of thiophene in synthesized isomers of COTh is confirmed by single‐crystal analysis 20–22 .…”

Recent Progress in Synthesis and Application of Thiophene Oligomers Based on Bithiophene Dicarbanions

“…The family of COTh s contains many isomers derived from different bithiophenes, such as 5 – 9 (Figure ). As early as 1974, Kauffmann and co‐workers reported the first two isomers of COTh ( 5 and 6 ) in 25 and 23% yields, respectively, and revealed their nonplanar saddle‐shaped geometry (Scheme ) 19. A small amount of 12‐membered macrocyclic compound 34 was afforded as a byproduct (Scheme ) 19b.…”

“…As early as 1974, Kauffmann and co‐workers reported the first two isomers of COTh ( 5 and 6 ) in 25 and 23% yields, respectively, and revealed their nonplanar saddle‐shaped geometry (Scheme ) 19. A small amount of 12‐membered macrocyclic compound 34 was afforded as a byproduct (Scheme ) 19b. Iyoda and co‐workers improved the yield for the preparation of 5 and 6 to around 40% yield by transmetalation and replacement of solvents (Scheme ) 20.…”

“…In work by the group of Kauffmann, 2,2'‐dibromo‐3,3'‐bithiophene was first treated with n BuLi to generate the Li 2 intermediate, and then intermolecular cyclization occurred with CuCl 2 as an oxidant to afford dimeric 8‐membered ring compound 5 and trimeric 12‐membered ring compound 34 19. We optimized the procedure to increase the yields of 5 and 34 in 2007 12.…”

Chiral tetrathienylene: synthesis and X-ray structure

“…Tetrakis(2,3-thienylene) (15)(16)(17) is an interesting ring system in which adjacent thiophene rings are alternatively connected between the α-positions (α, α-linkages) and β-positions (β, β-linkages) (Figure 1). Because of the out-of-plane twisting between the adjacent thiophene rings, these linkages correspond to the chiral axes; both α, α-linkages adopt identical axial chirality but opposite to that of the β, β-linkages, analogously to the linkages in tetraphenylenes (18)(19)(20)(21).…”