130822-07-0Relevant academic research and scientific papers
A CONVENIENT SYNTHESIS OF CYCLIC ETHERS FROM SILOXY CARBONYL COMPOUNDS
Homma, Koichi,Mukaiyama, Teruaki
, p. 259 - 262 (1989)
Five-seven membered cyclic ethers are prepared by one-pot procedure in good yields from γ-, δ-, and ε-siloxy carbonyl compounds, respectively, on treatment with silyl nucleophiles (triethylsilane, allyltrimethylsilane, trimethylsilyl cyanide, etc.) in the
Stereoselective synthesis of side chain-functionalized tetrahydropyrans from 5-hexenols
Fries, Patrick,Müller, Melanie Kim,Hartung, Jens
, p. 1336 - 1347 (2014/02/14)
Molecular oxygen stereoselectively converts 5-hexenols into 2,6-trans-, 2,5-trans-, and 2,4-cis-derivatives of 2-methyltetrahydropyran via oxidative cyclization/radical functionalization cascades, when activated by fluoro-substituted cobalt(II) bis-(β-diketonate) complexes in solutions of cyclohexa-1,4-diene (CHD). Aerobic 5-hexenol oxidations in solutions of bromotrichloromethane and CHD furnish products of 6-exo-bromocyclization, as exemplified by synthesis of diastereomerically pure 2,4,6-substituted tetrahydropyrans. The cobalt method extends to intermolecular alkene/alkanol cross-coupling and to multi-component reactions between dimethyl fumarate, CHD, a 5-hexenol, and dioxygen, providing α-tetrahydropyranyl-2-methyl succinates in synthetically useful yields.
4-(Arylsulfonyl)glycals in synthesis. Cation-mediated synthesis of 2,6- disubstituted dihydropyrans
Bailey, Jennifer M.,Craig, Donald,Gallagher, Peter T.
, p. 132 - 134 (2007/10/03)
4-(Arylsulfonyl)glycal 9, easily prepared from phenylsulfinic acid, acrolein and 2-phenyloxirane, undergoes efficient, stereoselective S(N)1' reactions on exposure to Lewis acidic reagent systems. Treatment of syn-9 with dimethyldioxirane gives a single glycal epoxide, which also is a substrate for intermolecular C-glycosidation reactions.
Photoreactions of Phenyl-Substituted N-(Pent-4-enyl-1-oxy)pyridine-1(1H)-thiones
Hartung, Jens,Hiller, Margit,Schmidt, Philipp
, p. 1014 - 1023 (2007/10/03)
A series of hitherto unknown N-(pent-4-enyl-1-oxy)pyridine-2(1H)-thiones (6) were prepared from substituted pent-4-enyl tosylates or benzylic chlorides.On irradiation with incandescent light heterocycles 6 liberated alkoxy radicals 2, which were studied for rearrangement reactions.Surprisingly, all transformations involving the 1-phenylpent-4-enyl-1-oxy radical (2a), for example, to give the substituted thioether 8, 2-bromomethyl-5-phenyltetrahydrofuran (11), or the tetrahydrofuran 14a, were not stereoselective.On the other hand 2-, 3-mono-, and 1,5-disubstituted pent-4-enyl-1-oxy radicals 2d-e and 2g cyclized in good yields and with good to excellent stereoselectivities to give the corresponding 2,4-cis- and 2,3-trans-phenyltetrahydrofurfuryl radicals 3d-e, and the trans-2-benzyl-5-methyl substituted intermediate 3g.The major reaction mode of the 4-phenylpent-4-enyl-1-oxy radical (2f) was the 6-endo cyclization, which afforded 3-phenyltetrahydropyran (13f) as the major product (endo:exo=93:7) after trapping with hydrogen donors.According to the experimental data of the present study, the unusual reactivity of the 1-phenylpent-4-enyl-1-oxy radical (2a) in 5-exo-trig ring closures could be caused by a coplanar arrangement of the benzyloxy moiety in the transition state of the cyclization.This interaction would lock the radical center in 2a in a preferred conformation, which would result in similar steric effects for both cis- and trans-cyclizations. - Keywords: alkoxy radicals; cyclizations; pyridinethiones; radicals; tetrahydrofurans
Stereoselective Syntheses of α-Substituted Cyclic Ethers and syn-1,3-Diols
Homma, Koichi,Takenoshita, Haruhiro,Mukaiyama, Teruaki
, p. 1898 - 1915 (2007/10/02)
In the presence of a catalytic amount of triphenylmethylium hexachloroantimonate or a catalyst system of antimony pentachloride, chlorotrimethylsilane and tin(II)iodide, α-substituted cyclic ethers are stereoselectively prepared from lactones by successiv
SUBSTITUTION REACTIONS OF 2-BENZENESULPHONYL CYCLIC ETHERS WITH CARBON NUCLEOPHILES
Brown, Dearg S.,Bruno, Maurizio,Davenport, Raymond J.,Ley, Steven V.
, p. 4293 - 4308 (2007/10/02)
Direct substitution of 2-benzenesulphonylcyclic ethers was studied using a variety of carbon nucleophiles.These nucleophiles included organozinc reagents (derived from aryl, vinyl and alkynyl Grignard reagents) or silyl enol ethers, silyl ketene acetals,
SUBSTITUTION REACTIONS OF 2-BENZENESULPHONYL CYCLIC ETHERS WITH SILYL ENOL ETHERS PROMOTED BY ALUMINIUM TRICHLORIDE
Brown, Dearg S.,Ley, Steven V.,Bruno, Maurizio
, p. 773 - 777 (2007/10/02)
Several cyclic ether 2-benzenesulphones were shown to react with silyl enol ethers in the presence of AlCl3 to give the corresponding alkylated products in good yield.Where substitution occured to give 2,6-disubstituted products there was a marked prefere
