Efficient Catalyst-Free Bi- And Triaroylation of Aromatic Rings in a Single Step

Abstract

The exceptional leaving group ability of the trimethylstannyl group in electrophilic aromatic substitutions makes possible the synthesis, in a single step, of bi- and triaroylarenes through the catalyst-free, regioselective reaction of bi- and tristannylarenes with different aroyl halides in o-dichlorobenzene as solvent. Specific di- and triketones are obtained in good to excellent yields (45-83%).

Synthesis of Mono-, Di-, and Tripalladated 1,3,5-Benzenetricarboxaldehyde Complexes

“…In spite of the tendencies observed, a simplistic interpretation of these 13 C chemical shifts in terms of the electron density should be avoided. 50 The 31 P NMR spectra of the phosphine complexes 1d, 1e, 2e, 3f show a single 31 P resonance, in agreement with the trans geometry of the complexes. As usual, the 31 P chemical shift decreases in the order PPh 3 (δ 21.1 ppm for 1d) > PMe 2 Ph (δ -7.5 ppm for 1e and -10.7 ppm for 2e) > PMe 3 (δ -18.8 ppm for 3f).…”

“…13 C{ 1 H}NMR (75.4 MHz, CDCl 3 ): δ 192.8 (s, 2C, CHO), 191.1 (s, 1C, CHO), 188.6 (t, 1C, C1-Pd, 2 J PC =5 Hz), 138.3 (s, 2C, C2-CHO), 134.7 (vt, 12C, ortho C's PPh 3 , 2 J PC þ 4 J PC =12 Hz), 133.5 (s, 1C, C4-CHO), 130.8 (s, 6C, para C's PPh 3 ), 130.1 (vt, 6C, ipso C's PPh 3 , 1 J PC þ 3 J PC =47 Hz), 128.7 (s, 2C, C3-Br), 128.2 (vt, 12C, meta C's PPh 3 3 J PC þ 5 J PC =10 Hz). 31…”

“…25 1,3,5-Tris(trimethylstannyl)benzene 26 has been obtained by several routes 20,24,27,28 and has been used in coordination, 29 transmetalation, 20,30 and C-C bond forming reactions. 28, 31 1,3,5-Tris(trimethylgermyl)benzene 32 and hexakis-(trimethylgermyl)benzene 33 have also been reported.…”

“…128.5 (2C, C3-Br), 128.2 (vt, 4C, meta C's PMe 2 Ph, 3 J PC þ 5 J PC =9 Hz), 13.4 (vt, 4C, PMe 2 Ph, 1 J PC þ 3 J PC =31 Hz). 31 Synthesis of [{PdBr(tmeda)} 2 {μ 2 -C 6 (CHO) 3 Br}] (2a). [Pd(dba) 2 ] (332 mg, 0.57 mmol), tmeda (86 μL, 0.57 mmol), and C 6 (CHO) 3 Br 3 (100 mg, 0.25 mmol) were mixed in dry degassed toluene (15 mL).…”

A new room‐temperature liquid, high‐performance tricyanate ester

“…Condensation of 4‐methoxyacetophenone ( 1 ) with N , N ‐dimethylformamide dimethyl acetal by the reported method15 gave the enaminoketone 2 16 in good yield. Cyclotrimerization of 2 using conditions of Elghamry17 gave the 1,3,5‐tribenzoylbenzene 3 18–20 in good yield. Triple Wittig reaction21, 22 of 3 with methyltriphenylphosponium bromide using potassium tert ‐butoxide as base gave the new triene 4 but only after partially selective recrystallization from heptane followed by silica gel chromatography to remove the byproduct triphenylphospine oxide (TPPO).…”