72445-18-2Relevant articles and documents
Catalytic Hydrothiolation: Counterion-Controlled Regioselectivity
Yang, Xiao-Hui,Davison, Ryan T.,Nie, Shao-Zhen,Cruz, Faben A.,McGinnis, Tristan M.,Dong, Vy M.
supporting information, p. 3006 - 3013 (2019/02/19)
In this Article, we expand upon the catalytic hydrothiolation of 1,3-dienes to afford either allylic or homoallylic sulfides with high regiocontrol. Mechanistic studies support a pathway in which regioselectivity is dictated by the choice of counterion associated with the Rh center. Non-coordinating counterions, such as SbF6-, allow for η4-diene coordination to Rh complexes and result in allylic sulfides. In contrast, coordinating counterions, such as Cl-, favor neutral Rh complexes in which the diene binds η2 to afford homoallylic sulfides. We propose mechanisms that rationalize a fractional dependence on thiol for the 1,2-Markovnikov hydrothiolation while accounting for an inverse dependence on thiol in the 3,4-anti-Markovnikov pathway. Through the hydrothiolation of an essential oil (β-farnesene), we achieve the first enantioselective synthesis of (-)-agelasidine A.
Use of aromatic radical-anions in the absence of THF. Tandem formation and cyclization of benzyllithiums derived from the attack of homo- and bishomoallyllithiums on α-methylstyrenes: Two-pot synthesis of cuparene
Cohen,Kreethadumrongdat,Liu,Kulkarni
, p. 3478 - 3483 (2007/10/03)
When a homo- or bishomoallyllithium, generated by reductive lithiation of the corresponding phenyl thioether by the radical anion lithium 1-(dimethylamino)naphthalenide (LDMAN), is added to α-methylstyrene, a tandem addition/cyclization to a phenyl-substituted five- or six-membered-ring occurs. The yields are compromised by polymerization of the α-methylstyrene, a process favored by tetrahydrofuran (THF), the solvent used to generate lithium aromatic radical anions. Thus, a new method of generating LDMAN (unsuccessful for other common radical anions) in the absence of THF has been developed. The radical anion can be generated and the reductive lithiation performed in dimethyl ether at -70 °C. After the addition of diethyl ether or other solvent, and evaporation of the dimethyl ether in vacuo, the α-methylstyrene is added and the solution is warmed to -30 °C. When the unsaturated alkyllithium is primary, no adduct forms in THF due to polymerization of the α-methylstyrene, but moderate yields are attained in a solvent containing mainly hexanes. It was also found that the cyclized organolithiums, which would have become protonated in the presence of THF, can be captured by an electrophile, even at ambient temperature. A two-pot synthesis, the most efficient reported, of the sesquiterpene (±)-cuparene in 46% yield, using this technology is reported.
SYNTHESIS WITH MANGANIC SALTS; PART III: SYNTHESIS OF 1,4-DIKETONES THROUGH MANGANIC ACETATE-MEDIATED ADDITION OF KETONE TO ISOPENTENYL SULFONES. ACETOXYLATION OF Β,Γ-UNSATURATED KETONES BY MANGANOUS AND CUPRIC ACETATES
Breuilles, Pascal,Uguen, Daniel
, p. 705 - 720 (2007/10/02)
Conditions have been found to selectively add ketones to isopentenyl sulfones.The major product, a ketone bearing a methylene group at the γ position, gave upon ozonolysis the corresponding 1,4-diketone.The usefulness of the overall process was illustrated by the efficient syntheses of jasmone and of one half of pyrenophorine.The γ-acetoxy conjugated enones that invariably formed during these additions resulted from the oxidation of an isomeric β,γ-unsaturated ketone by manganous and cupric acetates.Such an acetoxylation has been used to prepare 6β-acetoxy-cholestenone from cholesterol and also to prepare chrysanthemic acid.
C-PRENYLATION OF ISOPENTENYL DERIVATIVES WITH SULFONIUM SALTS
Badet, B.,Julia, M.,Marazano, C.
, p. 2007 - 2010 (2007/10/02)
Reaction of isopentenyl acetate (or n-butyl ether) with oil soluble prenyl sulfonium salts in the presence of a hintered amine leads to prenylation on the terminal carbon atom.
O-SILYLATED ENOLATE PHENYLTHIOALKYLATION: A NEW SYNTHESIS OF UNSATURATED 1,5-DICARBONYL COMPOUNDS.
Khan, Hassan A.,Paterson, Ian
, p. 2399 - 2402 (2007/10/02)
The O-silylated enolates of ketones and esters can be phenylthioalkylated by the chlorides (2) and (3) under ZnBr2-catalysis; ozonolysis and subsequent sulphoxide thermolysis then gives the corresponding unsaturated 1,5-dicarbonyl compounds.
A Versatile and Selective Route to Difunctional Trisubstituted (E)-Alkene Synthons via Zirconium-Catalyzed Carboalumination of Alkynes
Rand, Cynthia L.,Horn, David E. Van,Moore, Mark W.,Negishi, Ei-ichi
, p. 4093 - 4096 (2007/10/02)
The Zr-catalyzed carboalumination of propargyl and homopropargyl derivatives containing OH, OSiMe2Bu-t, SPh, or I provides, in a highly stereo- and regioselective manner, the corresponding (E)-(2-methylalkenyl)dimethylalkanes, which are convertible to var
