One-pot conversion of 1,1-dibromoalkenes into internal alkynes by sequential Suzuki–Miyaura and dehydrobromination reactions
作者:Giorgio Chelucci、Francesca Capitta、Salvatore Baldino、Gerard A. Pinna
DOI:10.1016/j.tetlet.2007.07.050
日期:2007.9
1-dibromoalkenes is reported. The method is hinged upon the Suzuki–Miyaura cross-coupling of 2-aryl- or 2-heteroaryl-1,1-dibromoalkenes with aryl or heteroaryl boronic acids or borate esters followed by dehydrobromination of the intermediate coupled products. Yields up to 89% were obtained.
The Stille Reaction of 1,1-Dibromo-1-alkenes: Preparation of Trisubstituted Alkenes and Internal Alkynes
作者:Wang Shen、Le Wang
DOI:10.1021/jo991116k
日期:1999.11.1
The Stille reaction of 1,1-dibromo-1-alkenes 1 with aryl- and vinylstannanes produces different products depending on the reaction conditions. When the reaction is run in toluene or 1,4-dioxane with tris(2-furyl)phosphine (TFP) as the ligand, (Z)-bromoalkenes 2 are obtained stereospecifically in good to excellent yields with most substrates. However, 2-aryl-1,1-dibromo-1-alkenes (1e,1g) having an electron-donating
the bromostilbenes ArCH=CBr(C6H4-4-R) can be prepared in significantly higher yields than by using NaH. The stereochemistry of two of the trisubstitutedvinylchlorides is unambiguously proven by X-ray structure determination. Thus for (Cl)PhC=CPh(Me), the isomer with the upfield NMR shift for the CH3 protons and for (Cl)PhC=C(Ph)(C6H4-4-Me), the isomer with the downfield NMR shift for the -C6H4-4-CH3
α-氯膦酸酯(OCH 2 CMe 2 CH 2 O)P(O)CHCl-C 6 H 4 -4-R [R = H(4),Me(5),OMe(6)],现在很容易在NaH存在下与酮R'C(O)R''反应(无需使用更昂贵的t- BuLi),得到三取代的乙烯基卤化物R'C(R'')= CCl(C 6 H 4 -4 -R),产量高。相应的α-bromophosphonates [R = H(7)中,Me(8)]无法与酮反应,得到对称的乙炔4-RC 6 H ^ 4 -CCC 6H 4 -4-R为可分离的产物,收率低。我们已经发现,回流的二甲苯中的K 2 CO 3是合成氯代苯乙烯的良好基础。使用该碱,与使用NaH相比,可以显着更高的收率制备溴化萘苯甲烷ArCH = CBr(C 6 H 4 -4-R)。通过X射线结构测定清楚地证明了两个三取代的氯乙烯的立体化学。因此,对于(Cl)PhC = CPh(Me),对于C
Shen, Wang, Synlett, 2000, # 5, p. 737 - 739
作者:Shen, Wang
DOI:——
日期:——
Stereospecific hydrodehalogenation of alkenyl bromides: a new approach to the synthesis of (E)-alkenes
作者:Giorgio Chelucci
DOI:10.1039/c4cc00345d
日期:——
The pair NaBH4-TMEDA and catalytic PdCl2(PPh3)2 in THF at room temperature is a mild and efficient system for the hydrodebromination of alkenyl bromides, providing a facile reduction procedure that allows completing the process advantageously, leading from aldehydes to (E)-alkenes.