38178-34-6Relevant articles and documents
Room-Temperature Palladium(II)-Catalyzed Direct 2-Arylation of Indoles with Tetraarylstannanes
Liu, Yuxia,Wang, Chao,Huang, Linjuan,Xue, Dong
supporting information, p. 1613 - 1618 (2020/09/15)
A palladium(II)-catalyzed direct 2-arylation of indoles by tetraarylstannanes with oxygen (balloon) as the oxidant at room temperature has been developed. Various tetraarylstannanes can be employed as aryl sources for 2-arylation of indoles in up to 89% yield, providing a practical and efficient catalytic protocol for accessing 2-arylindoles.
push-push and push-pull polystannanes
Dhindsa,Jacobs,Lough,Foucher
, p. 14094 - 14100 (2018/10/20)
The synthesis and characterization of polystannanes with push or pull moieties attached to the tin backbone are described. Precursor tetra aryl- (1, 2) stannanes were converted to mono- (3) and dichloro- (4, 5) stannanes by either sequential chlorination or by redistribution reactions with SnCl4. Compounds 4 and 5 were transformed to polymerisable tin dihydride monomers 6 and 7 using a large excess (10×) of NaBH4. Homopolymer 8 with electron donating aryl substituents (p-MeOC6H4-) was synthesized by dehydrogenative polymerization using Wilkinson's catalyst. Attempts to prepare the homopolymer 9 with electron withdrawing aryl substituents (p-CF3C6H4-) from the dehydrocoupling of 7 using similar conditions led only to the formation of low molecular weight oligomeric species. Two alternating polymers, 10 and 11, were synthesized by condensation polymerization of (n-Bu)2Sn(NEt2)2 with monomers 6 or 7. The first was a push-push alternating polymer, 10, comprised of a repeating unit consisting of two different electron donating groups (p-MeOC6H4-, n-Bu) at neighboring tin centres. The second was a push-pull alternating polymer, 11, bearing both an electron donating group (n-Bu) and a strongly electron withdrawing substituent (p-CF3C6H4-) at neighboring tin atoms. All small molecule stannanes and tin-containing polymers were characterized by NMR (1H, 13C, 119Sn, and where required 19F) spectroscopy, MS or EA. The absolute molecular weights of tin polymers (8, 10, 11) were determined by triple detection GPC and in the range of 1.07 × 104 to 1.95 × 104 Da. Rapid photodegradation of polymers was observed by UV-Vis spectroscopy, with a slower degradation observed for the push-pull polymer, 11, compared to the push-push polymer, 10.
The Ullmann coupling reaction: A new approach to tetraarylstannanes
Shaikh, Nadim S.,Parkin, Sean,Lehmler, Hans-Joachim
, p. 4207 - 4214 (2008/10/09)
Several iodobenzenes form tetraarylstannanes, in addition to other products, under reaction conditions typically employed for the Ullmann reaction, i.e., activated copper bronze (a copper-tin alloy) and 7 days at 230°C. The isolated yields of the tetraarylstannanes were low to good (8-58%). Significantly higher yields (54-64%) of tetraphenylstannane were obtained by the direct reaction of iodobenzene with an excess of tin powder (iodobenzene: tin = 1:1 w/w) under the same conditions. Crystal structure analysis reveals that tetrakis(4-carbomethoxyphenyl)stannane crystallizes in a tetragonal space group and has 4 symmetry, which is the case for many symmetrical tetraarylstannanes. However, tetrakis(2,4-dichlorophenyl)stannane, tetrakis(3,4-dichlorophenyl)stannane, and tetrakis(2,4-dimethylphenyl)stannane do not crystallize in a tetragonal space group and do not have real 4 symmetry.
