66291-52-9Relevant academic research and scientific papers
Borane-induced radical reduction of 1-alkenyl- and 1-alkynyl-λ3-iodanes with tetrahydrofuran
Ochiai, Masahito,Tsuchimoto, Yoshimi,Hayashi, Takanori
, p. 5381 - 5384 (2007/10/03)
Exposure of 1-alkenyl(phenyl)- and 1-alkynyl(phenyl)-λ3-iodanes to THF at room temperature in the presence of a catalytic amount of trialkylborane results in smooth reduction to give 1-iodo-1-alkenes and 1-iodo-1-alkynes as major products, respectively. The key step in the reductions probably involves a single-electron transfer from α-tetrahydrofuryl radical to the λ3-iodanes, which generates the labile [9-I-2] iodanyl radicals.
Vinylic SN2 Reaction of 1-Decenyliodonium Salt with Halide Ions
Okuyama, Tadashi,Takino, Tomoki,Sato, Koichi,Oshima, Kunio,Imamura, Shohei,Yamataka, Hiroshi,Asano, Tsutomu,Ochiai, Masahito
, p. 243 - 257 (2007/10/03)
Reactions of (E)-1-decenyl(phenyl)iodonium salt with halide ions are examined under various conditions. The products are those of substitution and elimination, usually (Z)-1-halo-1-decene and 1-decyne, as well as iodobenzene, except for the reaction with fluoride which leads exclusively to elimination. The labeling experiments show that the elimination induced by fluoride occurs via an α mode, while that caused by the other halides is a syn β elimination. Kinetic results show that the substitution and β elimination occur mainly from the halo-λ3 -iodane intermediate; the substitution occurs as a bimolecular reaction with the external halide ion while the elimination is a unimolecular (intramolecular) reaction. The imermediacy of the hypervalent λ3-iodane as well as of the iodate are also confirmed by UV spectroscopy. The secondary kinetic isotope effects, leaving group substituent effects, and pressure effects on the rate are compatible with the in-plane vinylic SN2 mechanism for the substitution with inversion. Some retained substitution product, (E)-1-halo-1-decene, is formed in polar protic solvents like trifluoroacetic acid, formic acid, and 1,1,1,3,3,3-hexafluoro-2-propanol. The reaction is very slow in these solvents and no sign of formation of ionic intermediates is found. This slow substitution with retention is considered to occur via ligand coupling within the halo-λ3-iodane intermediate.
Vinylic Organoboranes. 9. A General Stereospecific Synthesis of (Z)- and (E)-Disubstituted Alkenes via Organoboranes
Brown, Herbert C.,Basavaiah, Deevi,Kulkarni, Surendra U.,Bhat, Narayan G.,Prasad, J. V. N. Vara
, p. 239 - 246 (2007/10/02)
A general and stereospecific synthesis of (Z)-disubstituted alkenes using mono- and dihaloboranes is presented.The hydridation of dialkylhaloboranes in the presence of 1-alkynes provides the corresponding dialkylvinylboranes (1), representing the first general synthesis of such derivatives.Treatment with iodine in the presence of sodium methoxide induces the migration of one of the alkyl groups from boron to the adjacent carbon, followed by a rapid deiodoboronation to afford (Z)-disubstituted alkenes (2) in high yields.Similarly, the hydroboration of 1-alkynes with alkyl bromoboranes (R1BHBr*SMe2, 4) followed by iodination in the presence of sodium methoxide in methanol affords (Z)-disubstituted alkenes (2) in good yields.Both procedures constitute a general one-pot synthesis of (Z)- disubstituted alkenes from an alkene and 1-alkyne.A simple synthesis of Muscalure (7), the sex pheromone of the housefly (Musca domestica), is achieved in good yields.An alternative general stereospecific synthesis of (Z)- and (E)-disubstituted alkenes based on alkenylboronic esters is also described.
A General and Stereospecific Synthesis of Cis Alkenes via Stepwise Hydroboration: A Simple Synthesis of Muscalure, the Sex Pheromone of the Housefly (Musca domestica)
Brown, Herbert C.,Basavaiah, D.
, p. 3806 - 3808 (2007/10/02)
Base-induced iodination of the vinylborane intermediates, conveniently obtained via hydroboration of 1-alkynes with alkylbromoboranes (RBHBr*SMe2) provides cis-disubstituted alkenes in good yields.Muscalure, the insect pheromone of the housefly (Musca domestica), has been prepared in 59percent yield.
