Organocatalytic asymmetric addition of aliphatic thiols to nitro olefins and nitrodienes

The N-3,5-bis(trifluoromethyl)phenyl thiourea derivative of readily available chiral 1-benzyl-3-aminopyrrolidine was an effective organocatalyst for the asymmetric sulfa-Michael reaction. The adducts of aliphatic thiols to nitro olefins and nitrodienes were formed in good yields and with up to 87% ee in the presence of 2.5 mol % of the organocatalyst.     

Double michael addition reactions to tetrakis sulfonyl activated olefins

A new class of bis Michael adducts are prepared from 1,3‐bis‐[2‐(2‐arylethenesulfonyl)‐vinyl]‐benzenes and 1,4‐bis‐[2‐(2‐arylethenesulfonyl)‐vinyl]‐benzenes by double Michael addition reaction with active methylene compounds.     

Selective inhibition of the radical addition of thiols to olefins by iron pentacarbonyl

Conclusions The effect of Fe(CO)₅ and [Fe(CO)₃SC₂H₅]₂ on the competitive recombination of thiyl radicals and their addition to olefins was studied. Iron carbonyls selectively inhibit the addition and catalyze the recombination.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1647–1649, July, 1972.     

The electrophilic addition of thiols to olefins: A theoretical and experimental study

Density functional theory with the B3LYP hybrid functional and 6–31G* basis set was used to study the geometric and electronic structure of H₂C = CHR (R = H, CH₃, C₂H₅, C₃H₇, C₄H₉, and C₅H₁₁) olefins, their carbocations formed in the addition of the proton to the olefins, R′-S-H aliphatic thiols (R′ = H, CH₃, C₂H₅, and C₃H₇), the products of the addition of thiols to carbocations, and the final products of the addition of thiols to olefins. The proton affinity of the olefins and the products of the addition of thiols to olefins was calculated. The conclusion was drawn that the limiting stage in the nonradical addition of thiols to olefins catalyzed by acids was proton transfer from the protonated reaction product to the olefin. The theoretical results were compared with the experimental data on the electrophilic addition of polymercaptan to heptene-1.     

Electrocatalytic fluoroalkylation of olefins

Under electrocatalysis conditions, the perfluoroalkylation of α-methylstyrene by the nickel complex NiBr₂bipy proceeds with the formation of dimeric products of addition of perfluoroalkyl radicals to the double bond.     

Electrocatalytic fluoroalkylation of olefins

An efficient nickel-catalyzed method devoted to the direct addition of perfluoroalkyl halides (I, Br) to α-methylstyrene is described. This procedure allows for synthesis of compounds resulting from addition-dimerization in good yields.     

Enantioselective conjugate addition of aliphatic thiols to divergently activated electron poor alkenes and dienes

Divergently activated double bonds in electron poor 4-oxo-butenoates and (2E,4E)-6-oxo-2,4-dienoates underwent stereoselective and regioselective addition of mercaptans catalyzed by simple Cinchona alkaloids. Application of quinine and quinidine afforded both enantiomers of the 1,4-adducts with respect to the ketone carbonyl group in ees of up to 80%. Single recrystallization of some adducts resulted in further enrichment of up to 99%ee.     

Concise approach to novel isothiazolidinone phosphotyrosine mimetics: microwave-assisted addition of bisulfite to activated olefins

[reaction: see text] A novel and efficient synthesis of isothiazolidinone protein tyrosine phosphatase mimetics is presented. A practical, regiospecific microwave-assisted addition of bisulfite to activated olefins, including unprecedented reactions with styrene derivatives, is highlighted.     

Addition of primaryN-nitroamides to activated olefins

PrimaryN-nitrosulfamides readily undergo addition to acrolein and vinyl ketones to yieldN--oxoalkyl-N-nitrosulfamides. The presence of a second substituent at the double bond hinders the reaction.N-Nitrourethane reacts with activated carbonyl compounds and -nitroolefins.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1261–1263, July, 1994.     

Palladium-catalyzed addition reaction of polyhaloalkanes to olefins

Pd(OAc)₂ combined with phosphines catalyzes homolytic cleavage of the C—Cl bond of CCl₄ and CCl₃CO₂CH₃ leading to facile addition to olefins under mild conditions. BrCCl₃ also reacts with olefins to give 1,1,1-trichloro-3-bromoalkanes. The reaction is accelerated under CO atmosphere, and the presence of bases such as NaOAc or K₂CO₃ is essential to attain high yields of the adducts.     

Rongalite-initiated addition of perfluoroalkyl iodides to olefins

Perfluoroalkyl iodides reacted with olefins in aqueous acetonitrile in the presence of Rongalite-sodium bicarbonate under mild conditions to give the corresponding 1:1 adducts in moderate to high yields. The formation of these products and the orientation of the addition seemed to show that radicals took part in the reaction. This provides a convenient method for perfluoroalkylation.     

Michael addition of novel acyl anion equivalents generated by the electroreduction of oxazolinium salts to activated olefins

Electroreduction of oxazolinium salts gave novel acyl anion equivalents (AAEs), and the Michael addition of these AAEs to activated olefins has been found to be promoted effectively by the addition of chlorotrimethylsilane into the reaction system. This reaction was applied to the synthesis of cis-jasmone and dihydrojasmone.     

The electrophilic addition of selenenyl thiocyanates to olefins

Benzeneselenenyl thiocyanate in methanol reacts with olefins to give adducts; kinetic data for attack upon styrenes are presented.     

Rare-earth-catalyzed C-H bond addition of pyridines to olefins

An efficient and general protocol for the ortho-alkylation of pyridines via C-H addition to olefins has been developed, using cationic half-sandwich rare-earth catalysts, which provides an atom-economical method for the synthesis of alkylated pyridine derivatives. A wide range of pyridine and olefin substrates including α-olefins, styrenes, and conjugated dienes are compatible with the catalysts.     

Molecular mechanism of hydrogen bromide addition to olefins

Experimental results on the products and the kinetics of the hydrogen bromide addition to alkenes-1 in non-polar solvents and on complex formation in hydrogen bromide-olefin-solvent systems are reviewed. Theoretical calculations concerning hydrogen bromide-olefin complexes are used along with the experimental evidence to suggest a molecular mechanism of addition involving intermediate cyclic structures.     

Organocatalytic asymmetric addition of alcohols and thiols to activated electrophiles: efficient dynamic kinetic resolution and desymmetrization protocols

Bifunctional urea-based cinchona alkaloid derivatives have been shown to promote highly efficient DKR reactions of azalactones using an alcohol nucleophile. The optimum catalyst is remarkably insensitive to the steric bulk of the amino acid residue, allowing alanine-, methionine-, and phenylalanine-derived azalactones to undergo DKR with unprecedented levels of enantioselectivity using a synthetic catalyst. The first DKR of these substrates by thiols and the highly enantioselective desymmetrization of a meso-glutaric anhydride by thiolysis are also reported.