Improved synthesis of 8-oxabicyclo[3.2.1]octanes <i>via</i> tandem C–H oxidation/oxa-[3,3] Cope rearrangement/aldol cyclization
作者:Lin Liu、Hai-Long Cheng、Wen-Qiang Ma、Si-Hua Hou、Yong-Qiang Tu、Fu-Min Zhang、Xiao-Ming Zhang、Shao-Hua Wang
DOI:10.1039/c7cc08511g
日期:——
A tandem C–H oxidation/oxa-[3,3] Cope rearrangement/aldol reaction of allylic silylethers promoted by T+BF4−(tempo oxoammonium tetrafluoroborate)/ZnBr2 has been successfully developed allowing the efficient construction of 8-oxabicyclo[3.2.1]octanes and their analogs with a wide substrate scope.
Le Triflate de Bismuth(III) Comme Catalyseur Dans la Reaction de Carbonyl-Diels-Alder
作者:Adyl Bernard、Bernard Garrigues
DOI:10.1080/10426500210673
日期:2002.4.1
In presence of bismuth(III) triflate, a carbonylated electrophile (ethyl mesoxalate or glyoxylate) and usual diene led selectively (60-100) the hetero carbonyl-Diels-Alder reaction with the ene reaction product. Bi(OTf) 3 exhibits strong catalytic activity and reacts under mild conditions. En présence de triflate de bismuth(III) le mésoxalate et le glyoxylate d'éthyle réagissent avec des diènes usuels
在三氟甲磺酸铋 (III) 存在下,羰基化的亲电子试剂(甲基草酸乙酯或乙醛酸乙酯)和普通二烯选择性地(60-100)导致杂羰基-Diels-Alder 反应与烯反应产物。Bi(OTf) 3 表现出很强的催化活性并且在温和的条件下反应。En présence de triflate de bismuth(III) le mésoxalate et le glyoxylate d'éthyle réagissent avec des diènes usuels pour donner un mélange de carbonyl-Diels-Alder et du produit de la ène réaction。Bi(OTf) 3 présente une forte activité catalytique et réagit dans des conditions douces。
The carbonyl-Diels-Alder reaction catalyzed by bismuth (III) chloride
作者:Hélène Robert、Bernard Garrigues、Jacques Dubac
DOI:10.1016/s0040-4039(97)10791-2
日期:1998.3
In presence of bismuth (III) chloride, a carbonylated electrophile (ethyl mesoxalate or glyoxylate) and usual diene led selectively (65 to 100%) the hetero carbonyl-Diels-Alder reaction with the ene reaction product. BiCl3 exhibits strong catalytic activity and, compared with previous literature, reacts under mild conditions.
A series of bis-phosphine monoxide (BPMO) palladium(II) and platinum(II) cationic complexes of the type [M(BPMO-κ2-P,O)2][X]2 (M = Pd, Pt; BPMO = Ph2P–(CH2)n–P(O)Ph2 with n = 1 (dppmO), 2 (dppeO), 3 (dpppO); X = BF4, TfO) were prepared from the corresponding chlorides [MCl2(BPMO-κ1-P)2] upon treatment with 2 equiv. of AgX in wet acetone/CH2Cl2 or MeOH solutions. They were characterized by 1H and 31P1H}
Asymmetric hetero Diels-Alder reactions and ene reactions catalyzed by chiral copper(II) complexes
作者:Mogens Johannsen、Karl Anker Joergensen
DOI:10.1021/jo00123a007
日期:1995.9
A new copper(II) bisoxazoline-catalyzed reaction of glyoxylate esters with dienes leading to the hetero Diet-Alder product and the ene product in high yield and with a high enantiomeric excess (ee) has been developed. The hetero Diels-Alder product:ene product ratio is in the range 1:0.6 to 1:1.8 and is dependent on both the chiral ligand attached to the metal, the glyoxylate ester, and the reaction temperature. The scope of the copper(II) bisoxazoline-catalyzed reaction of glyoxylate esters with dienes is demonstrated by the reaction of a variety of different dienes with ethyl and isopropyl glyoxylate, and it is shown that a simple substrate such as 1,3-butadiene reacts to give the hetero Diels-Alder product in 55% yield with an ee of 87%. Furthermore, the synthetic application of the reaction is demonstrated by the synthesis of a highly interesting synthon for sesquiterpene lactones in high yield and diastereoselectivity, and with a very high ee from 1,3-cyclohexadiene and ethyl glyoxylate using a copper(II) bisoxazoline as the catalyst. A mechanism for the hetero Diels-Alder reaction, which accounts for the enantioselectivity in the reactions, is proposed.