42437-23-0Relevant articles and documents
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.
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.
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