Ultrasound-Assisted Rapid Synthesis of Functionalized 1,2-Teraryls by Ring Transformation Methodology

Abstract

The function of styryl acetate as a carbanion nucleophile source has been explored in the ring transformation reaction of 2H-pyranones. The ultrasound assisted carbanion induced ring transformation of 4-amino-6-aryl-3-cyano-2H-pyran-2-ones using (E)-styryl acetate in the presence of KOH and DMF at room temperature is presented as an alternative strategy for the synthesis of functionalized 1,2-teraryls in high yields. This metal-free methodology provides easy access to a series of 1,2-teraryls and features broad functional group tolerance and mild reaction condition. Single crystal X-ray diffraction analysis of 4-(piperidin-1-yl)-6-(thiophen-2-yl)-[1,1'-biphenyl]-3-carbonitrile indicated that the crystal belongs to monoclinic system with a P21 space group having twisted aryl rings.

Transition-metal-free synthesis and photophysical studies of highly functionalized (E)-stilbenes

“…Based on previous studies, a plausible mechanism for the ring transformation of 2-oxo-6-phenyl-4-Amino-2H-pyran-3carbonitrile to highly functionalized stilbene is illustrated in Scheme 3. [52][53][54] The reaction mechanism starts with the in situ generation of enolate in the presence of a base, possibly by deprotonation of the active methylene group of 12.…”

“…Based on previous studies, a plausible mechanism for the ring transformation of 2-oxo-6-phenyl-4-Amino-2 H -pyran-3-carbonitrile to highly functionalized stilbene is illustrated in Scheme 3. 52–54 The reaction mechanism starts with the in situ generation of enolate in the presence of a base, possibly by deprotonation of the active methylene group of 12 . The enolate formed acts as a nucleophile and attacks the C-6 position of 6-aryl-2 H -pyran-2-ones 9 through Michael addition to generate an intermediate [A] .…”

Synthesis of fluorescent aromatic species via ring transformation of α-pyranones and their application in OLEDs, chemosensors, and cell imaging

“…Additionally, we were able to devise a new strategy utilizing ( E )-styryl acetate 26 as the carbanion source to convert α-pyranones 8 into 1,2-terphenyl derivatives 27 at room temperature using powdered KOH and dry DMF under irradiation (Scheme 8). 63 A comprehensive analysis of previous research indicated that this was the first instance where ( E )-styryl acetate was employed as the carbanion source in ring transformation reactions involving α-pyranones.…”

“…, carbanion C , during the ring transformation process of pyranone due to its greater stability arising from both resonance and inductive effects (Scheme 9). 63…”

Metal free synthesis of thermally stable blue fluorescent m-terphenyls by ring transformation of 2H-pyran-2-ones: chemical synthesis, spectroscopy and computational studies

“…22 Furthermore, it was observed that the poly aromatic compounds with donor-acceptor cores have exceptional uorescence. [23][24][25][26][27][28][29] To highlight the photophysical characteristics of extended conjugation systems, we have synthesized phenyl substituted m-terphenyl scaffolds.…”