135006-32-5Relevant articles and documents
Reductive decomplexation of biscobalthexacarbonyl acetylenes into olefins
Hosokawa, Seijiro,Isobe, Minoru
, p. 2609 - 2612 (1998)
The decomplexation of acetylene biscobalthexacarbonyl complexes can usually be achieved under oxidative condition. We had found other reductive conditions with endo-cyclic complexes, and recently other reductive conditions with both endo- and exo-cyclic complexes using either tributyltin hydride or triethylsilane. The original acetylene derivatives were transformed selectively either into the corresponding cis olefins or cis- vinylsilanes.
Cross-Coupling Reaction of Alkenyl Sulfoximines and Alkenyl Aminosulfoxonium Salts with Organozincs by Dual Nickel Catalysis and Lewis Acid Promotion
Erdelmeier, Irene,Bülow, Gerd,Woo, Chang-Wan,Decker, Jürgen,Raabe, Gerhard,Gais, Hans-Joachim
supporting information, p. 8371 - 8386 (2019/06/04)
In this article, the cross-coupling reaction (CCR) of exocyclic, axially chiral, and acyclic alkenyl (N-methyl)sulfoximines with alkyl- and arylzincs is described. The CCR generally requires dual Ni catalysis and MgBr2 promotion, which is effective in diethyl ether but not in THF. NMR spectroscopy revealed a complexation of alkenyl sulfoximines by MgBr2 in diethyl ether, which suggests an acceleration of the oxidative addition through nucleofugal activation. The CCR of alkenyl sulfoximines generally proceeds in the presence of Ni(dppp)Cl2 as a precatalyst and MgBr2 with alkyl- and arylzincs with a high degree of stereoretention at the C and the S atom. CCR of axially chiral alkenyl sulfoximines with Ni(PPh3)2Cl2 as a precatalyst and ZnPh2 does not require salt promotion and is stereoretentive. The reaction with Zn(CH2SiMe3)2, however, demands salt promotion and is not stereoretentive. CCR of axially chiral α-methylated alkenyl sulfoximines afforded persubstituted axially chiral alkenes with high selectivity. Alkenyl (N-triflyl)sulfoximines engage in a stereoretentive CCR with Grignard reagents and Ni(PPh3)2Cl2. Ni-Catalyzed and MgBr2-promoted CCR of E-configured acyclic alkenyl sulfoximines and aminosulfoxonium salts with ZnPh2 and Zn(CH2SiMe3)2 is stereoretentive with Ni(dppp)Cl2 and Ni(PPh3)2Cl2. CCRs of acyclic alkenyl sulfoximines and alkenyl aminosulfoxonium salts, carrying a methyl group at the α position, take a different course and give alkenyl sulfinamides under stereoretention at the S and C atom. CCR of acyclic, exocyclic, and axially chiral alkenyl sulfoximines has been successfully applied to the stereoselective synthesis of homoallylic alcohols, exocyclic alkenes, and axially chiral alkenes, respectively.
Synthesis of solandelactone F, constanolactone A and an advanced intermediate towards solandelactone e from a common synthetic intermediate
Yalla, Raju,Raghavan, Sadagopan
, p. 4572 - 4592 (2019/05/16)
The stereoselective synthesis of solandelactone F, constanolactone A and an advanced intermediate towards solandelactone E, from a common synthetic intermediate, is disclosed. The propargylic sulfide stereocenter is created stereoselectively via carbon-carbon bond formation in the reaction of α-chloro sulfides with alkynylzinc reagents via 1,2-asymmetric induction by a β-siloxy group. The characteristic 1,4-diol motif of the natural products is introduced by a [2,3] sigmatropic rearrangement of an allylic sulfoxide or by the Mislow-Evans-Braverman rearrangement of a propargylic sulfoxide followed by stereoselective reduction of the ensuing α,β-unsaturated ketone. Unlike earlier reports, the C11/C9 carbinol center is created with excellent stereocontrol and derivatives of natural products differing at C14/C12 can be readily obtained. Catalytic asymmetric protocols and substrate-controlled asymmetric induction are utilized for the efficient introduction of the stereogenic centers.