27686-42-6Relevant articles and documents
Selenenate Anions (PhSeO?) as Organocatalyst: Synthesis of trans-Stilbenes and a PPV Derivative
Zheng, Zhipeng,Trofymchuk, Oleksandra S.,Kurogi, Takashi,Varela, Elena,Mindiola, Daniel J.,Walsh, Patrick J.
, p. 659 - 666 (2020)
The selenenate anion (RSeO?) is introduced as an active organocatalyst for the dehydrohalogen coupling of benzyl halides to form trans-stilbenes. It is shown that RSeO? is a more reactive catalyst than the previously reported sulfur analogues (sulfenate anion, RSO?) and selenolate anions (RSe?) 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, Mn (average molecular weight) up to 13,000 and ? (dispersity) of 1.15. (Figure presented.).
Catalytic enantioselective allyl- and crotylboration of aldehydes using chiral diol·SnCl4 complexes. Optimization, substrate scope and mechanistic investigations
Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
supporting information; experimental part, p. 8481 - 8490 (2009/02/02)
We report a novel class of C2-symmetric chiral diols derived from the hydrobenzoin skeleton. The combination of these diols with SnCl 4 under Yamamoto's concept of Lewis acid assisted Bronsted acidity (LBA catalysis) leads to high levels of asymmetric induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate units in >95:5 dr and up to 98:2 er. The X-ray crystal structure of the optimal diol·SnCl4 complex, Vivol (4m)·SnCl 4, unambiguously shows the Bronsted acidic character of this LBA catalyst and its highly dissymmetrical environment. Further controls have ruled out a possible boron transesterification mechanism with the chiral diol and point to LBA catalyst-derived activation of the pinacol allylic boronates 1. Due to slow dissociation of the diol·SnCl4 complex, a small excess of diol is required in order to suppress a competing racemic cycle catalyzed by free SnCl4.
Synthesis of succinimido[3,4-b]indane and 1,2,3,4,5,6-hexahydro-1,5-methano-3-benzazocine-2,4-dione by sequential alkylation and intramolecular arylation of enolates derived from N,N,N'N'-tetramethylbutanediamides and N,N,N'N'-tetramethylpentanediamides
Dandekar, Sushama A.,Greenwood, Stacey N.,Greenwood, Thomas D.,Mabic, Stephane,Merola, Joseph S.,Tanko, James M.,Wolfe, James F.
, p. 1543 - 1553 (2007/10/03)
The tricyclic title compounds, 4 and 5, were synthesized by initial alkylation of the lithium monoenolates of N,N,N',N'-tetramethylbutanediamide (6) and N,N,N',N'-tetramethylpentanediamide (19) with 2-iodobenzyl chloride in liquid NH3 at -60°C to afford 2-(2-iodobenzyl)-N,N,N',N'-tetramethylbutanediamide (9) and 2-(2-iodobenzyl)-N,N,N',N'-tetramethylpentanediamide (20) in yields of 88 and 87%, respectively. Treatment of 9 with KNH2 in liquid NH3 resulted in formation and intramolecular arylation of the less-substituted α-enolate to produce trans-1,2-bis(N,N-dimethylcarboxamido)indane (10a) in 60% yield. Selective hydrolysis of 10a with aqueous Na2O2 gave trans-1-(N,N-dimethylcarboxamido)indane-2-carboxylic acid (17), which was then converted to bridged succinimide 4 by transformation to trans-1-(N,N-dimethylcarboxamido)indane-2-carboxamide (10c) followed by cyclization of this mixed primary/tertiary amide by means of NaH in refluxing THF. Treatment of 20 with KNH2 in liquid NH3 led to intramolecular arylation and accompanying ammonolysis to afford trans-1-(N,N-dimethylcarboxamido)-1,2,3,4-tetrahydronaphthalene-3-carboxamide (21b). Conversion of 21b to 5 was similarly effected by means of NaH. Experiments designed to test the mechanistic aspects of the intramolecular arylations provided evidence for competing aryne and SET pathways.
