82797-12-4Relevant academic research and scientific papers
Photoinduced metalation of nonactivated C-Cl bonds with samarium diiodide: Synthesis of alkenes with high (Z)-selectivity through β-elimination reactions
Concellon, Jose M.,Rodriguez-Solla, Humberto,Simal, Carmen,Huerta, Monica
, p. 5833 - 5835 (2007/10/03)
(Chemical Equation Presented) The photoinduced metalation of nonactivated C-Cl bonds of O-acetyl chlorohydrins is promoted by samarium diiodide. As a result of this, β-elimination of O-acetyl chlorohydrins is achieved, affording the corresponding (Z)-alkenes with total or high stereoselectivity.
Opposite stereochemical effects exerted by CeCl3 and TiCl4 on the Lewis acid mediated reduction of α-alkyl-β-ketophosphine oxides with metallic hydrides: A highly stereoselective protocol for the synthesis of syn and anti α-alkyl-β-hydroxyphosphine oxides
Bartoli, Giuseppe,Bosco, Marcella,Dalpozzo, Renato,Marcantoni, Enrico,Sambri, Letizia
, p. 1941 - 1950 (2007/10/03)
A general, highly efficient methodology for obtaining both syn and anti α-hydroxyphosphine oxides by reduction of the corresponding α-ketophosphine oxides is described. The nature of the Lewis acid was found to be pivotal in determining the outcome of these reactions. Strongly chelating TiCl4 led to the anti isomer in high diastereoisomeric excess in noncoordinating solvents (CH2Cl2) at -78°C with BH3/py as reducing agent, while nonchelating CeCl3 gave a high excess of the syn isomer in coordinating solvents (THF) at the same temperature with LiBH4 as reducing agent. In the latter case, CeCl3 is essential in achieving high yields and stereoselectivity, since it allows the reaction to be performed at low temperatures. Otherwise, higher temperatures (0 °C) are required, which lower both yields and selectivities. Moreover, each step of the protocol for the synthesis of stereodefined disubstituted olefins from alkylphosphine oxides (Warren's modification of the Homer procedure) has been optimized, and the optimized procedure has been applied to the synthesis of muscalure, the pheromone of the domestic fly.
Novel ortho-Alkoxy-Substituted Phosphorus Ylides and Their Stereoselectivity in Wittig Reactions
Jeganathan, Suruliappa,Tsukamoto, Masamitsu,Schlosser, Manfred
, p. 109 - 111 (2007/10/02)
The stereochemistry of the reactions between tris(2-methoxymethoxypheny)phosphonioethanide (1f), -butanide (2f), and -phenyl-methanide (3f) and a variety of aldehydes was investigated.Ylides having a β-unbranched aliphatic sidechain, such as 2f, and saturated straight-chain aldehydes give olefins with unprecedented cis-selectivity (cis/trans ca. 200:1).
HINDERED ORGANOBORON GROUPS IN ORGANIC SYNTHESIS. 13. THE DIRECT PRODUCTION OF KETONES FROM ALIPHATIC ALDEHYDES BY A UNIQUE VARIANT OF THE BORON-WITTIG REACTION
Pelter, Andrew,Smith, Keith,Elgendy, Said,Rowlands, Martin
, p. 5643 - 5646 (2007/10/02)
In the presence of trifluoroacetic anhydride or N-chlorosuccinimide, aliphatic aldehydes react with dimesitylboron stabilised carbanions to give after work up, the corresponding ketones, a process wich is unique among Wittig type reactions.Yields of ketones are satisfactory in all cases except those involving the anion derived from the parent compound dimesitylmethylborane, wich give the corresponding alkenes.
HINDERED ORGANOBORON GROUPS IN ORGANIC SYNTHESIS. 14. STEREOSELECTIVE SYNTHESIS OF ALKENES BY THE BORON-WITTIG REACTION USING ALIPHATIC ALDEHYDES
Pelter, Andrew,Smith, Keith,Elgendy, Said,Rowlands, Martin
, p. 5647 - 5650 (2007/10/02)
In the presence of HX, carbanions Mes2BCHLiR1 react with aliphatic aldehydes to give alkenes.The stereochemistry of product alkene depends upon the nature of HX.
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.
