77568-65-1Relevant articles and documents
Selective aerobic oxidation of cyclic ethers to lactones over Au/CeO2 without any additives
Liu, Shulin,Li, Shaopeng,Shen, Xiaojun,Wang, Yanyan,Du, Juan,Chen, Bingfeng,Han, Buxing,Liu, Huizhen
supporting information, p. 2638 - 2641 (2020/03/10)
Selective oxidation of ethers to lactones with O2 as a benign oxidant using Au/CeO2 as the catalyst has been developed. The oxygen vacancies and Au0 species on the surface of CeO2 contribute to the activation of O2. The excellent selectivity of lactones is due to the adsorption of ethers and activation of the C(sp3)-H bond on Au/CeO2.
Stereoselective preparation of six diastereomeric quatercyclopropanes from bicyclopropylidene and some derivatives
Von Seebach, Malte,Kozhushkov, Sergei I.,Schill, Heiko,Frank, Daniel,Boese, Roland,Benet-Buchholz, Jordi,Yufit, Dmitry S.,De Meijere, Armin
, p. 167 - 177 (2007/10/03)
Diastereomeric meso- and d,l-bis(bicyclopropylidenyl) (5) were obtained upon oxidation with oxygen of a higher-order cuprate generated from lithiobicyclopropylidene (4) in 50 and 31 % yield, respectively. Their perdeuterated analogues meso-[D14]- and d,l-[D14]-5 were obtained along the same route from perdeuterated bicyclopropylidene [D 8]-3 (synthesized in six steps in 7.4% overall yield from [D8]-THF) in 20.5% yield each. Dehalogenative coupling of 1,1-dibromo-2- cyclopropylcyclopropane (6) gave a mixture of all possible stereoisomers of 1,5-dicyclopropylbicyclopropylidene 16 in 69% yield, from which (Z)-cis-16 was separated by preparative gas chromatography (26% yield). The crystal structure of meso-5 looks like a super-position of the crystal structures of two outer bicyclopropylidene units (3) and one inner s-rrans-bicyclopropyl unit, whereas the two outer cyclopropyl moieties adopt a gauche orientation with respect to the cyclopropane rings at the inner bicyclopropylidene units in (Z)-cis-16. Birch reduction with lithium in liquid ammonia of meso-5 and d,l-5 gave two pairs of diastereomeric quatercyclopropanes trans,trans-(R*,S*, R*, S*)-17/cis,trans-(R*,S*,R*,R*)-18 and trans,trans-(R*,S*,S*,R*)-19/cis,trans-(R*, S*,S*,S*)-20 in 97 and 76% yield, respectively, in a ratio 9:1 for every pair. The latter diastereomer was also obtained as the sole product by Birch reduction of (Z)-cis-16 in 96% yield. Under the same conditions, tetradecadeuterio analogues trans,trans-[D14]-(R*S*, R*,S*)-17/cis,trans-[D14]-(R*, S*,R*, R*)-18 (8:1) and trans,trans[D14]-(R*,S*,S*, R*)-19/cis,trans-[D14](R*,S*,S*,S*)-20 (12:1) were prepared from mwo-[D14]-5 and d,l-[D14]-5 in 37 and 63 % yield, respectively. Reduction of meso-5 with diimine gave the cis,cisquatercyclopropane (S*,S*,R*,R*)-21 as the main product (58% yield) along with the cis,trans-diastereomer (S*,S*, R*,S*)-18 (29% yield). Thus, five of the six possible diastereomeric quatercyclopropanes were obtained from meso-5, d,l-5, and (Z)-cis-16. The X-ray crystal structure analyses of transjrans-(R*,S*,R*,S*)- 17 and cis,cis(S*,S*,R*,R*)-21 revealed for the both an unusual conformation in which the central bicyclopropyl unit adopts an s-fran.s-(antiperiplanar) orientation with φ=180.0°, and the two terminal bicyclopropyl moieties adopt a synclinal conformation with φ = 49.8 and 72.0°, respectively. In solution the vicinal coupling constants 〈3JH,H〉 in trans,trans(R*,R*, R*,S*)-[D14]-17, trans,trans(R*,S*,S*, R*)-[D14]-19, trans,trans(R*,S*,R*,R*)- [D14]-18 and trans,cis(R*,S*,S*,S*)-[D 14]-20 were found to be 4.1, 4.7, 5.9 and 5.9 Hz, respectively. This indicates a predominance of the all-gauche conformer in (R*,S*, R*,S*)-17 and a decreasing fraction of it in this sequence of the other diastereomers.
Kinetics of Oxidation of Aromatic Hydrocarbons and Tetrahydrofuran by trans-Dioxoruthenium(VI) Complexes
Che, Chi-Ming,Tang, Wai-Tong,Wong, Kwok-Yin,Li, Chi-Keung
, p. 3277 - 3280 (2007/10/02)
The kinetics of oxidation of aromatic hydrocarbons and tetrahydrofuran by trans-VILO2>2+ 1 = 6,7,14,15,16,17,18,19-octahydro-14,18-dimethyl-13H-dibenzodioxadiazacyclopentadecine, L2 = N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)propylenediamine and L3 = meso-2,3,7,11,12-pentamethyl-3,7,11,17-tetraazabicycloheptadeca-1(17),13,15-triene> has been studied.In acetonitrile the second-order rate constants follow the order: toluene 2+ (L = L1 or L2) are 16 and 12:1 respectively.In the oxidation of tetrahydrofuran by trans-1O2>2+, k2 was found to be 0.170 mol-1 dm3 s-1 at 298 K with a measured kinetic isotope effect of 20:1.A linear correlation between log(rate constant) and E0(RuVI-RuIV) for the oxidation of tetrahydrofuran has been observed.The activation parameters for the oxidation reactions have also be determined.A hydrogen-atom abstraction mechanism is suggested for the oxidation of C-H bonds by trans-dioxoruthenium(VI) complexes.
