42437-24-1Relevant academic research and scientific papers
Stereoselective alkene isomerization over one position
Larsen, Casey R.,Grotjahn, Douglas B.
supporting information; experimental part, p. 10357 - 10360 (2012/08/08)
Although controlling both the position of the double bond and E:Z selectivity in alkene isomerization is difficult, 1 is a very efficient catalyst for selective mono-isomerization of a variety of multifunctional alkenes to afford >99.5% E-products. Many reactions are complete within 10 min at room temperature. Even sensitive enols and enamides susceptible to further reaction can be generated. Catalyst loadings in the 0.01-0.1 mol% range can be employed. E-to-Z isomerization of the product from diallyl ether was only -6 times as fast as its formation, showing the extremely high kinetic selectivity of 1.
Ti/Ni-based multimetallic system for the efficient allylation of carbonyl compounds
Martinez-Peragon, Angela,Millan, Alba,Campana, Araceli G.,Rodriguez-Marquez, Irene,Resa, Sandra,Miguel, Delia,Alvarez De Cienfuegos, Luis,Cuerva, Juan M.
supporting information; experimental part, p. 1499 - 1503 (2012/04/23)
A mild method for the allylation of carbonyl compounds is presented. This methodology allows the allylation of a broad range of carbonyl compounds starting with allyl carbonates as pronucleophiles. Noteworthy is that ketones, infrequent substrates in other related protocols, are suitable substrates under these reaction conditions. Moreover, the reaction proceeds at room temperature with the use of catalytic amounts of both Ni and Ti catalysts. The success of this strategy is based on the perfect match between the late transition metal (nickel) and the radical reagent (titanium). The use of Ni instead of Pd widens the scope of this transformation and makes this method more economical.
Mesoporous aluminosilicate-catalyzed allylation of carbonyl compounds and acetals
Ito, Suguru,Hayashi, Akira,Komai, Hirotomo,Yamaguchi, Hitoshi,Kubota, Yoshihiro,Asami, Masatoshi
experimental part, p. 2081 - 2089 (2011/04/19)
A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both carbonyl compounds and acetals with allylsilanes to afford the corresponding homoallyl silyl ethers and homoallyl alkyl ethers, respectively. Both the mesoporous structure and the presence of aluminum moiety were indispensable for the high catalytic activity of Al-MCM-41. Moreover, Al-MCM-41 could catalyze the reaction of acetals chemoselectively in the presence of the corresponding carbonyl compounds. The solid acid catalyst Al-MCM-41 could be recovered easily by filtration and could be reused three times without a significant loss of catalytic activity.
Ti-catalyzed Barbier-type allylations and related reactions
Estevez, Rosa E.,Justicia, Jose,Bazdi, Btissam,Fuentes, Noelia,Paradas, Miguel,Choquesillo-Lazarte, Duane,Garcia-Ruiz, Juan M.,Robles, Rafael,Gansaeuer, Andreas,Cuerva, Juan M.,Oltra, J. Enrique
experimental part, p. 2774 - 2791 (2009/12/03)
Titanocene(III) complexes, easily generated in situ from commercial Ti IV precursors, catalyze Barbiertype allylations, intramolecular crotylations (cyclizations), and prenylations of a wide range of aldehydes and ketones. The reaction displays surprising and unprecedented mechanistic subtleties. In cyclizations a fast and irreversible addition of an allyl radical to a TiIII-coordinated carbonyl group seems to occur. Intermolecular additions to conjugated aldehydes proceed through a coupling of a Ti IV-bound ketyl radical with an allyl radical. Reactions of ketones with allylic halides take place by the classical addition of an allylic organometallic reagent. The radical coupling processes enable transformations such as the highly regioselective α-prenylation that are otherwise difficult to achieve. The mild reaction conditions and the possibility to employ titanocene complexes in only catalytic quantities are highly attractive features of our protocol. These unusual properties have been taken advantage of for the straightforward synthesis of the natural products rosiridol, shikalkin, and 12-hydroxysqualene.
Allylation and crotylation of ketones and aldehydes using potassium organotrifluoroborate salts under lewis acid and montmorillonite k10 catalyzed conditions
Nowrouzi, Farhad,Thadani, Avinash N.,Batey, Robert A.
supporting information; experimental part, p. 2631 - 2634 (2009/10/02)
Two convenient highly diastereoselective protocols for the allylation and crotylation of ketones using practical, air- and water-stable potassium allyl and crotyltrifluoroborate salts have been developed. BF3-OEt 2 and montmorillonit
Evaluation of Chelation Effects Operative during Diastereoselective Addition of the Allylindium Reagent to 2- And 3-Hydroxycyclohexanones in Aqueous, Organic, and Mixed Solvent Systems
Paquette, Leo A.,Lobben, Paul C.
, p. 5604 - 5616 (2007/10/03)
The unprotected 2- and 3-hydroxycyclohexanones 1-8 were prepared by methods that skirted as much as possible their proclivity for α-ketol rearrangement (where the possibility for such isomerization exists). The diastereofacial selectivity of their reactio
Ligand effects in selective addition reactions of organoindium reagents with carbonyl compounds
Reetz, Manfred T.,Haning, Helmut
, p. 117 - 120 (2007/10/03)
The reaction of the allyl indium sesquibromide (CH2 =CHCH2)3In2Br3 with four equivalents of a bulky lithium alkoxide ((CH3)3COLi or (CH3)3CCH2OLi) results in modified reagents which show unusual degrees of chemo-and stereoselectivity in reactions with carbonyl compounds. For example, in reactions with cyclohexanone derivatives, 84-93% equatorial attack with preferential formation of the axial alcohols is observed. Chiral aldehydes react in a highly diastereoselective manner.
First preparation of allyl vanadium reagents in a mixed solvent of THF and HMPA (HMPA = hexamethylphosphoric triamide) and their application to allylation of carbonyl compounds
Kataoka, Yasutaka,Makihira, Isamu,Tani, Kazuhide
, p. 7083 - 7086 (2007/10/03)
Allylation of carbonyl compounds with allyl bromide mediated by a vanadium(II) complex in a mixed solvent of THF and HMPA (HMPA = hexamethylphosphoric triamide) has been accomplished. Coordination of HMPA to a vanadium metal is essential for the stabilization of the allyl vanadium species.
A Novel Entry into Wittig Rearrangements - A Stereoselective -Wittig Rearrangement with Inversion of Configuration at the Carbanion Center
Hoffmann, Rolf,Brueckner, Reinhard
, p. 1957 - 1964 (2007/10/02)
The O,Se ketal 10, through lithium naphthalenide induced reductive cleavage of its Csp3-Se bond, was converted into the α-lithio ether 11a with an equatorially oriented C-O bond.At -78 deg C, 11a undergoes a rapid -Wittig rearra
Indium in Organic Synthesis: Indium-Mediated Allylation of Carbonyl Compounds
Araki, Shuki,Ito, Hirokazu,Butsugan, Yasuo
, p. 1831 - 1833 (2007/10/02)
Indium-mediated allylation of a variety of ketones and aldehydes afforded excellent yields of the corresponding homoallylic alcohols under very mild reaction conditions.
