1192-37-6Relevant articles and documents
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Sauers
, p. 4873,4875 (1959)
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Kinetics and regioselectivity of ring opening of 1-bicyclo[3.1.0] hexanylmethyl radical
Kantorowski, Eric J.,Le, Daniel D.,Hunt, Caleb J.,Barry-Holson, Keegan Q.,Lee, Jessica P.,Ross, Lauren N.
, p. 1593 - 1596 (2008)
(Chemical Equation Presented) Rate constants for the rearrangement of 1-bicyclo[3.1.0]-hexanylmethyl radical (2) to 3-methylenecyclohexenyl radical (3) and 2-methylenecyclopentyl-1-methyl radical (1) were measured using the PTOC-thiol competition method. The ring-expansion pathway is described by the rate equation, log(k/s-1) = (12.5 ± 0.1) - (4.9 ± 0.1)/θ; the non-expansion pathway is described by log(k/s-1) = (11.9 ± 0.6) - (6.9 ± 0.8)/θ. Employing the slower trapping agent, tri-n-butylstannane, favors methylenecyclohexane over 2-methyl-methylenecyclopentane by more than 120:1 at ambient or lower temperatures.
Adjusting the features of active metallocene ziegler systems for their potential use as carbon-carbon coupling catalysts in organic synthesis
Thiele, Sven,Erker, Gerhard
, p. 201 - 207 (1997)
A variety of bent metallocene dichloride/methylalumoxane catalysts, derived from the zirconocene complexes 10, 12-18, have been employed in intramolecular olefin-coupling reactions yielding monomeric or dimeric products. This was achieved by using optimized reaction conditions employing low substrate concentrations (1.0-1.8 M) and rather long reaction times. Under these particular conditions, 1,5-hexadiene was cyclodimerized to give l-methylene-3-(cyclopentylmethyl)cyclopentane (11). 1,6-Heptadiene was cleanly converted to methylenecyclohexane, and cis-1,2-divinylcyclopentane (19) and cis-1,2-divinylcyclohexane (22) were cyclized to yield 2-methylenebicyclo[3.3.0]octane (20) and 7-methylenebicyclo[4.3.0]nonane (23), respectively. In many cases, the cyclization products were accompanied by isomers originating from double-bond shift reactions that often occur rapidly at these catalyst systems under the specific reaction conditions chosen to keep the products in the monomeric regime. VCH Verlagsgesellschaft mbH.
Kauffman, T.,Ahlers, H.,Joussen, R.,Kriegesmann, R.,Vahrenhorst, A.,Woltermann, A.
, (1978)
Wittig Reagents Bound to Cross-Linked Polystyrenes
Bernard, Margaret,Ford, Warren T.
, p. 326 - 332 (1983)
Insoluble benzyltriarylphosphonium and methyltriarylphosphonium salts have been prepared on 2percent and 8percent divinylbenzene cross-linked polystyrene and on 20percent divinylbenzene cross-linked macroporous polystyrene.Phosphoranes were generated with sodium methoxide or sodium ethoxide in THF and with the dimethylsulfinyl carbanion in Me2SO from the benzyl- and methylphosphonium salts, respectively.Reactions of the phosphoranes with a variety of aldehydes and ketones provided alkenes in 73-96percent yields (by GLC analysis) with the 2percent cross-linked polymer, 52-77percent yields with the 8percent cros s-linked polymer, and 72-87percent yields with the 20percent cross-linked macroporous polymer.The rates of phosphorane generation and alkene formation depend on the polymer, decreasing in the order 2percent > 20percent macroporous > 8percent cross-linked.The fraction of E double bond product from the benzylphosphonium salt and either benzaldehyde or cinnamaldehyde is greater with the 20percent cross-linked macroporous polymer than with the 2percent cross-linked polymer.The byproduct polymer-bound phosphine oxides were reduced to phosphines with trichlorsilane, and the phosphines were reused for Wittig synthesis.A quantitative 31P-NMR analysis of phosphine and phosphine oxide residues in polystyrene gels is reported.
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Kotani
, p. 1767,1771 (1966)
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Organic Photochemistry with 6.7-eV Photons: Rigid Homoallylic Alcohols. An Inverse Norrish Type II Rearrangement
Studebaker, Joel,Srinivasan, R.,Ors, Jose A.,Baum, Thomas
, p. 6872 - 6874 (1980)
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THE DIMESITYLBORON GROUP IN ORGANIC SYNTHESIS. 4. THE 'BORON WITTIG' REACTION
Pelter, Andrew,Singaram, Bakthan,Wilson, John W.
, p. 635 - 636 (1983)
Anions generated α- to a dimesitylboron group readily condense with aldehydes and ketones.Elimination of Mes2BOLi then leads to alkenes in a boron analogue of the Wittig reaction.
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Chum,Wilson
, p. 1257 (1976)
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Greenwald,R. et al.
, p. 1128 - 1129 (1963)
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Synthesis of sp 3-Enriched β-Fluoro Sulfonyl Chlorides
Gurbanov, Rustam,Sokolov, Andriy,Golovach, Sergey,Melnykov, Kostiantyn,Dobrydnev, Alexey V.,Grygorenko, Oleksandr O.
, p. 1771 - 1784 (2020/12/28)
A three-step approach to the synthesis of sp 3-enriched β-fluoro sulfonyl chlorides starting from alkenes is reported. The method was successfully applied to a wide range of acyclic and cyclic substrates, bearing either an exocyclic or an endocyclic double bond. The procedure worked with a wide range of substrates and tolerated a number of functional and protecting groups. Moreover, the target cyclic compounds were obtained as single cis diastereomers on a multigram scale. The title compounds are promising building blocks for drug discovery that can be used to obtain sp 3-enriched β-fluoro and α,β-unsaturated sulfonamides.
Stereoselective Diboration of Spirocyclobutenes: A Platform for the Synthesis of Spirocycles with Orthogonal Exit Vectors
Nóvoa, Luis,Trulli, Laura,Parra, Alejandro,Tortosa, Mariola
supporting information, p. 11763 - 11768 (2021/04/26)
The diastereo- and enantioselective diboration of spirocyclobutenes provides a platform for the rapid preparation of a wide variety of chiral spirocyclic building blocks. The chemoselective functionalization of the carbon-boron bond in the products, including a stereospecific sp3-sp2 Suzuki–Miyaura cross-coupling reaction, provides a powerful tool to control the directionality and the nature of the exit vectors in the spirocyclic framework.
A Rare-Earth-Metal Ensemble of the Tebbe Reagent: Scope of Coligands and Carbonyl Olefination
Anwander, Reiner,Birkelbach, Verena M.,Dietrich, H. Martin,Kracht, Felix,Maichle-M?ssmer, C?cilia,Stuhl, Christoph
, p. 3490 - 3504 (2020/10/09)
Treatment of the half-sandwich complexes CpRLn(AlMe4)2 (CpR = C5Me5, C5Me4SiMe3; Ln = Y, La, Lu) with the mild halogenido transfer reagents SiMe3X (X = Cl, Br, I) resulted in efficient and selective halogenido/tetramethylaluminato exchange. Depending on the size of the rare-earth metal, dimeric [CpRLn(AlMe4)(μ-X)]2 (Ln = Y, Lu) and decametallic [CpR3La3(AlMe4)2(μ-X)4]2 could be obtained. Donor (THF)-induced tetramethylaluminato cleavage gave access to methyl-free mixed methylidene/halogenido complexes CpR3Ln3(μ-X)3(μ3-X)(μ3-CH2)(THF)3 for yttrium (X = Cl, Br) and lanthanum (X = Cl, Br, I) in good yields. Additionally, mixed methylidene/halogenido Y(III) complexes could be obtained via methyl/halogenido exchange employing (C5Me5)3Y3(μ-Me)3(μ3-Me)(μ3-CH2)(THF)2 and SiMe3X via tetramethylsilane elimination. All methylidene complexes were probed in olefination reactions and found to act as efficient Schrock-type nucleophilic carbenes converting ketones and aldehydes into the respective terminal alkenes. Such reactivity is as high as that of the prominent Tebbe reagent but is less tolerant toward sterically demanding and functionalized substrates (such as esters). In contrast to the Tebbe reagent, complexes CpR3Ln3(μ-X)3(μ3-X)(μ3-CH2)(THF)3 polymerize δ-valerolactone in an efficient manner, generating polylactones with molecular weight distributions Mw/Mn as low as 1.13. Moreover, the bromido variant of the Tebbe reagent, Cp2Ti(μ-CH2)(μ-Br)AlMe2, is described, underlying similar synthesis limitations: that is, the coformation (and hence cocrystallization) of the trivalent species Cp2Ti(μ-Br)2AlMe2.