钯催化炔碘与有机锡化合物交叉偶联反应

以钯为催化剂,DMEDA为配体,实现了碱性条件下炔碘化合物与有机锡化合物的Stille交叉偶联反应,合成了一系列芳环上含有甲基、甲氧基及卤原子的中间炔烃。该方法底物适应范围广、产率高,为C—C键的构筑提供了一条新路径。     

Studies on the Pd catalyzed reaction of perfluoroalkyl and polyfluoroalkyl iodides with tertiary amines

Pd catalyzed reaction of perfluoroalkyl and polyfluoroalkyl iodides with tertiary amines gave enamines(1) which on acid hydrolysis afforded enaminones(2), or aldehydes(3).     

The reaction of secondary perfluoroalkyl iodides with zinc

Evidence for the existence of two mechanistic pathways for the reaction of secondary perfluoroalkyl iodides with zinc has been obtained. At high concentration of secondary iodides, a bimolecular homolytic type reaction of the iodide on the zinc surface to yield dimers appears to be preferred. When the reaction is carried out under dilute conditions, an ionic type mechanism appears to predominate. This paper also shows that the substrate itself can influence the reaction route.     

A facile synthesis of perfluoroalkyl vinyl iodides and their palladium-mediated cross-coupling reactions

Catalytic amounts of zinc, as low as 10 mol %, in the presence of trifluoroacetic acid (TFA) initiate the radical addition of perfluoroalkyl iodides to terminal alkynes with high regio- and stereoselectivities. Palladium-mediated cross-coupling of these (E)-perfluoroalkyl vinyl iodides allows for a facile synthesis of potentially useful fluoroorganic intermediates.     

Studies on fluoroalkylation and fluoroalkoxylation: 8. Palladium(0)-catalyzed addition reaction of fluoroalkyl iodides with alkynes

Fluoroalkyl iodide R_fI [R_F=(CF₂)_nCl, n=2, 4, 6; CF₃(CF₂)_n, n=1, 3; H(CF₂)₄] reacted with alkyne (CH≡CC₄H₉; CH≡CSiMe₃; CH≡CC₆H₅) in the presence of catalytic amounts of tetrakis (triphenylphosphine) palladium (0) to give a mixture of E and Z-fluoroalkylated adduct. The reaction could not be catalyzed by dichloro-bis(triphenylphosphine)palladium (II) and fluoroalkyl complex of palladium (II). 2-Nitro-2-nitrosopropane partly suppressed the reaction. It is believed that the reaction proceeds through a free radical intermediate rather than fluoroalkyl complex of palladium (II).     

全氟碘代烷的光溴化

全氟溴代烷(R_FBr,下同)曾应用为灭火剂和X射线造影剂.为了研究R_FBr进行脱溴亚磺化反应的可能性,促使我们探索R_FBr的新合成方法.经典的合成方法主要为Hunsdiecker反应,最近我们发展了从全氟亚磺酸盐合成R_FBr的方法.文献曾记载R_FI热溴化制取R_FBr,本文报道全氟碘代烷的光溴化反应用于合R_FBr.     

An efficient photoinduced iodoperfluoroalkylation of carbon-carbon unsaturated compounds with perfluoroalkyl iodides

Dependent on the selection of the light sources employed, the photoinduced iodoperfluoroalkylation of a variety of unsaturated compounds takes place efficiently via a radical mechanism. Upon irradiation with a xenon lamp through Pyrex (hnu >300 nm), terminal alkenes (R-CH=CH2) and alkynes (R-C triple bond CH) undergo iodoperfluoroalkylation with perfluoroalkyl iodides (RF-I) regioselectively, providing R-CH(I)-CH2-RF and R-C(I)=CH-RF, respectively. In the case of terminal allenes (R-CH=C=CH2), the photoinduced iodoperfluoroalkylation occurs selectively at the terminal double bond, giving the corresponding beta-perfluoroalkylated vinylic iodides (R-CH=C(I)-CH2-RF) in good yields. The photoinitiated reaction of vinylcyclopropanes (c-C3H5-C(R)=CH2) with RF-I proceeds via the rearrangement of cyclopropylcarbinyl radical intermediates to the homoallylic radical intermediates, and the corresponding 1,5-iodoperfluoroalkylated products (I-(CH2)2CH=C(R)-CH2-RF) are obtained in high yields. Isocyanides (R-NC), as C-N unsaturated compounds, also undergo the xenon-lamp-irradiated iodoperfluoroalkylation to provide the corresponding 1,1-adducts (R-N=C(I)-RF) in good yields. Furthermore, the present photoinitiation procedure can be applied to the iodotrifluoromethylation of unsaturated compounds, when the xenon-lamp-irradiated reactions are conducted under the refluxing conditions of excess CF3-I.     

亚磺化脱卤研究IX.仲碘代全氟烷的合成及其反应研究

合成了仲碘代全氟烷衍生物CF~3CFI(CF~2)~2O(CF~2)~2SO~2F(3),CF~3(CFI(CF~2)~2O(CF~2)~2SO~3Na(4),CF~3CFI(CF~2)~nCl(7an=2,7bn=4)及CF~2(CF~2)~3OCFICF~3(8),研究了它们与连二亚硫酸钠的反应,并用烯烃作为自由基截捕剂加入反应体系中,得到了1:1仲碘代全氟烷与各类烯烃的加成物.     

Studies on sulfinatodehalogenation: XVI. Sodium dithionite-initiated addition of perfluoroalkyl iodides to terminal alkynes

Reaction of perfluoroalkyl iodides with a series of alkynes under sulfinatodehalogenation condition gave a mixture of E/Z adducts very readily in high yield, thus constituted a mild, convenient and effective new method for the addition of perfluoroalkyl iodides to alkynes. Under the same condition, in the presence of 1-hexyne perfluoroalkyl bromide and 1,1,1-trichlorotrifluoroethane reacted only to give sulfinates as the major products. A radical mechanism was proposed for the addition reaction.     

Palladium(0)-catalyzed cyclization reaction of polymer-supported aryl iodides with 1,2-allenyl carboxylic acids. A facile solid-phase synthesis of butenolides

[reaction--see text] Aryl iodides anchored to Merrifield resin via the linkages between a carboxyl, hydroxyl, or hydroxymethyl group and the benzylic chloride moiety in the resin reacted efficiently with 1,2-allenic carboxylic acids under the catalysis of Pd(0) to afford polymer-supported butenolides. Polysubstituted butenolides can be easily cleaved from the resins by Lewis acid-catalyzed processes in good yields and purities.     

亚磺化脱卤研究 VII. 全氟碘代烷与SO~3^-的反应

全氟碘代烷R~FI[R~F=CF~3(CF~2)~5(1a);H(CF~2)~4(1b);H(CF~2)~8(1c);Cl(CF~2)~6(1d);Cl(CF~2)~8(1e)Cl(CF~2)~8(1f);;NaO~3S(CF~2)~20(CF~2)~2(1g);NaO~3S(CF~2)~2O(CF~2)~4(1h)]及α,ω-二碘化物I(CF~2)~nI[n=4(1i);n=6(1j)]与Ce^4^+-亚硫酸氢钠于70℃左右、pH3～4的溶液中反应,形成相应的全氟烷基亚磺酸盐,产率70～85%。全氟氯代烷和全氟溴代烷在同样条件下未能发生反应。     

A facile photoinduced iodoperfluoroalkylation of dienes, diynes, and enynes with perfluoroalkyl iodides via selective radical cyclization

Perfluoroalkyl iodides serve as excellent mediators for the radical cyclization of dienes, diynes, and enynes upon irradiation with near-UV light, providing the corresponding iodoperfluoroalkylated cyclic compounds in moderate to good yields.     

Studies on sulfinatodehalogenation: IX. Synthesis and reaction of secondary perfluoroalkyl iodides

Several derivatives of secondary perfluoroalkyl iodides such as CF₃CFI(CF₂)₂O(CF₂)₃SO₂F (3), CF₃CFI(CF₂),O(CF₂)₂SO₃Na (4), CF₃CFI(CF₃)_n Cl (n=2, 7a; n=4, 7b) and CF₃(CF2)₂-OCFICF₃ (8) were synthesized using known methods, their reaction with sodium dithionite was studied and various olefins were added into the reaction system as radical traps to yield the 1:1 radical adducts.     

Studies on sulfinatodehalogenation XIX. The reaction of perfluoroalkyl iodides and perfluoroalkanesulfonyl bromides with conjugated dienes

Perfluoroalkyl iodides reacted with conjugated dienes in aqueous acetonitrile solution in the presence of sodium dithionite at room temperature to give dimerization products, whereas, perfluoroalkanesulfonyl bromides reacted with conjugated dienes to form 1,4-adducts under actinic irradiation.     

Palladium catalyzed atom-efficient cross-coupling reactions of triarylbismuths with aryl iodides and aryl triflates

The atom-efficient cross-coupling of triarylbismuths with aryl iodides or aryl triflates using catalytic Pd(OAc)₂/PPh₃ and K₃PO₄ as base in DMF at 90 °C to afford the corresponding functionalized biaryls in high yields is reported.     

Electrochemical preparation of some organotin compounds

Organotin dihalides R₂SnX₂ (X  Cl, Br, I) and their adducts with bidentate donor ligands have been prepared in high yield by the direct electrochemical reaction of metallic tin with alkyl or aryl halides in organic media at room temperature. Dimethyltin diiodide can be converted to tetramethyltin by reaction with methyl iodide at a cadmium anode. Electrochemical halide abstraction has been used to prepare R₆Sn₂ (R  Me, Ph) from the corresponding R₃Sn halide. The mechanism of these reactions is discussed.     

Platinum complex catalyzed reaction of tributyltin cyanide with alkynes

In the presence of a catalytic amount (5 mol%) of a platinum complex, tributyltin cyanide (1) reacts with dimethyl- (2a) or diethyl acetylenedicarboxylate (2b) to afford cyanostannylation adducts (3a, b) in excellent yields. The reaction proceeds highly selectively affording only a (Z)-isomer. The compounds 3a, b are novel products which possess synthetically useful cyano, alkenylstannyl and alkoxycarbonyl functionalities in the same molecule. Two alkoxycarbonyl functionalities may be indispensable on each alkyne carbon to accomplish the cyanostannylation reaction. Reaction with terminal alkynes gave the stannylated product (6).     

Synthesis of fluorinated telomers. Part 1. Telomerization of vinylidene fluoride with perfluoroalkyl iodides

Thermal and redox-induced telomerizations of vinylidene fluoride (VDF) with linear (n-C₄F₉I) or branched (i-C₃F₇I) perfluoroalkyl iodides have been performed. In both cases, thermal telomerizations led to telomeric-type distributions of the first five (from linear telogen) or the first three (from branched telogen) adducts produced, with better yields at higher temperatures. The redox-initiated telomerization was more selective since it led to the first two adducts only. For both reactions, mono- and di-adducts were isolated and characterized by ¹H and ¹⁹F NMR spectroscopy. Interestingly, both the diadducts were composed of two isomers (i.e. the expected telomer and R_FCH₂CF₂CF₂CH₂I). Two mechanisms are proposed and it is assumed that the products may be obtained either by chain propagation or by stepwise telomerization. In addition, attack of the electrophilic radical on the nucleophilic side of VDF is discussed.