Regioselective SN2 opening of vinylic epoxides with trialkylzincates and trialkylaluminates
The use of trialkylorganozincates and tetraalkylaluminates allows regioselective SN2 nucleophilic opening of vinylic epoxides. The reaction occurs with an anti-substitution pattern and can be applied to a wide range of substrates. We also show that the solvent and the structure of the epoxide have an influence on the substitution products' ratio. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Catalytic Regiodivergent Kinetic Resolution of Allylic Epoxides: A New Entry to Allylic and Homoallylic Alcohols with High Optical Purity
A novel regiodivergent kinetic resolution of a series of allylic epoxides with alkylzinc reagents is described. Results demonstrate the potential of chiral copper-phosphoramidite catalysts for enantiomer differentiation of allylic epoxides, allowing a chiral catalyst-stereoregulated synthesis of cyclic allylic and homoallylic alcohols with high optical purities.
Regioselective SN2 opening of α,β-ethylenic epoxides by RLi-BF3 combination
Organolithium reagents effect a regioselective SN2 nucleophilic cleavage of α,β-ethylenic epoxides only when BF3·Et2O is added. The reaction works with a variety of RLi reagents and with cyclic as well as acyclic epoxides. The Royal Society of Chemistry 2000.
EFFICIENT AND REGIOCONTROLLED NICKEL(II)-CATALYZED ALKYLATION OF 2-ALKYL-1,3-DIOXEP-4-ENES BY GRIGNARD REAGENTS: A SIMPLE ROUTE TO ALLYLIC ALCOHOLS
The regio- and the stereochemistries of the NidppeCl2 catalyzed alkylation of 2-alkyl-1,3-dioxep-4-enes by Grignard reagents are not affected by the nature of the C2 substituent; in any case, allylic alcohols are the main reaction products and nearly pure Z isomers are almost quantitatively obtained when either secondary or tertiary Grignard reagents are used.A rationale for the reaction is proposed.
NICKEL(II)-CATALYZED ALKYLATION OF 2-METHYL-1,3-DIOXEP-4-ENE BY GRIGNARD REAGENTS: AN EFFICIENT AND SELECTIVE ROUTE TO ALLYLIC ALCOHOLS
Allylic alcohols are formed, in good yields, through the regiocontrolled Cl2Nidppe-catalyzed alkylation of 2-methyl-1,3-dioxep-4-ene by Grignard reagents .Highly pure Z alcohols arise when secondary and tertiary aliphatic Grignards are used.