Selenenate Anions (PhSeO⁻) as Organocatalyst: Synthesis of trans‐Stilbenes and a PPV Derivative

Abstract

The selenenate anion (RSeO À ) is introduced as an active organocatalyst for the dehydrohalogen coupling of benzyl halides to form trans-stilbenes. It is shown that RSeO À is a more reactive catalyst than the previously reported sulfur analogues (sulfenate anion, RSO À ) and selenolate anions (RSe À ) in the aforementioned reaction. This catalytic system was also applied to the benzylic-chloromethyl-coupling polymerization (BCCP) of a bis-chloromethyl arene to form ppv (poly(p-phenylene vinylene))-type polymers with high yields, M n (average molecular weight) up to 13,000 and Đ (dispersity) of 1.15.

Transition-metal-mediated reduction and reversible double-cyclization of cyanuric triazide to an asymmetric bitetrazolate involving cleavage of the six-membered aromatic ring

“…The latter compound is isolable, stable, and crystalline, [62][63][64] and its formation is plausible due to the known redox relationships between amines/amides and hydrazine. 65 R 2 N−NR 2 has a reported 1 H NMR upfield chemical shift of 0.2 ppm in benzene-d 6 solvent, distinct from the chemical shifts of hexamethyldisiloxane (0.12) 66 and hexamethyldisilazane (0.10) 67 . The analysis of the crude reaction mixture of the synthesis of 2c reveals the formation of R 2 N−NR 2 , ( Figure S3) and provides an explanation for the observed redox processes, and implies the following reaction stoichiometry:…”

Synthesis of Stilbenes by Cyanide/Base-Mediated Coupling of Benzylic Chlorides and Alcohols

“…11 An interesting organocatalytic protocol allows for the homocoupling of benzylic halides in the presence of phenyl seleneate as the catalyst with a stoichiometric amount of a base. 12 In addition, arylacetonitriles can be coupled with benzylic alcohols in the presence of either a base in DMF 13 or a nickel catalyst and a base (Scheme 1 ). 14 However, many of these previous stilbene syntheses suffer from either a poor E / Z selectivity or require special starting materials that are not commercially available.…”

Recent advances in synthesis of stilbene derivativesviacross-coupling reaction

“…In 2020, the Mindiola and Walsh research group developed a procedure for trans -stilbenes 31c and a poly( p -phenylene vinylene) (PPV) derivative using a new organocatalyst (Scheme 39). 54 For this purpose, they applied benzylic phenyl selenoxide 31b , which transformed to selenenate anion (RSeO − ) A in the dehydrohalogen coupling reaction of benzyl chlorides and bromides 31a . In the reaction, deprotonation of benzylic phenyl selenoxide 31b by KN(SiMe 3 ) 2 as a base formed the nucleophilic carbanion A , which coupled with benzyl halide 31a .…”