Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes

Abstract

Reaction of bis(diethylamino)acetylene (1)

Synthesis, characterization and antifungal testing of 3,4-dihydropyrimidin-2(1H)-(thio)ones containing boronic acids and boronate esters

“…4. The B-O bond distances of B(1)-O(1) 1.353(2) and B(1)-O(2) 1.356(3) Å are typical for those observed in related structures where the boron is three coordinate [26][27][28][29]. Likewise, the sum of the angles around boron for 4b are 360.00 (18) o , indicating that the boron atom is three coordinate.…”

Reactivity of the [η2‐Bis(tert‐butylsulfonyl)acetylene](carbonyl)(η5‐cyclopentadienyl)cobalt Complex Towards Electron‐Rich and ‐Poor Acetylenes

“…Melting points (uncorrected) were obtained on a Büchi apparatus, using capillaries which were filled under nitrogen and sealed. Complex (1), [9] 2-(diethylamino)-1-phenylthioacetylene (2a), [10] 2-(diethylamino)-1-(diphenylphosphanyl)acetylene (2b), [11] 2-(diethylamino)-1-phenylacetylene (2c), [12] 1-(diethylamino)-2-bis(diethylaminoboryl)acetylene, [13] 1-catecholboryl-2-phenylacetylene, [12] 1-dithiocatecholboryl-2-phenylacetylene, [12] and (PhC 2 ) 2 S (2g) [14] were prepared according to literature procedures.…”

“…The 1 H NMR spectrum of 3g shows the expected multiplets (δ = 6.9-7.1 ppm) for the aryl hydrogens in addition to two singlets (δ = 1.19 and 1.27 ppm) for the tert-butyl groups and the Cp resonance (δ = 5.01 ppm). In the 13 C NMR spectrum, the signals (δ = 58.6-75.2 ppm) for the cyclobutadiene ring are found along with the Cp resonance at δ = 83.5 ppm. The molecular-ion peak of 3g was detected with the correct isotopic distribution in the mass spectrum.…”

“…In the 13 C NMR spectra of 3a-c, the signals for C 5 H 5 (δ = 82-84 ppm) were detected along with the aryl carbon atoms (δ = 125.0-138.9 ppm). EI-MS data confirmed the formation of complexes 3a-c by the appearance of the molecular-ion peaks with the expected isotopic pattern.…”

“…The 1 H NMR spectra of 3a-c show two singlets in the region δ = 1.2-1.5 ppm for the tert-butyl groups in addition to the Cp resonance (δ = 5.0-5.3 ppm). In general, the characteristic feature of the 13 C NMR spectra is the chemical shift of the cyclobutadiene ring atoms, which have values of between δ = 75 and 85 ppm.…”