Stereoselective Synthesis of Cyclic Guanidines by Directed Diamination of Unactivated Alkenes
作者:Artur K. Mailyan、Kyle Young、Joanna L. Chen、Bradley T. Reid、Armen Zakarian
DOI:10.1021/acs.orglett.6b02778
日期:2016.11.4
method for a directed stereoselective guanidinylation of alkenes is described. The guanidine unit can be delivered as an intact fragment by a hydroxy or carboxy group, usually with a high level of stereocontrol. After the guanidine delivery, the directinggroup can be cleaved under exceptionally mild conditions, typically by alcoholysis in the presence of acetic acid. Broad functionalgroup tolerance
Catalyzed by PdCl2, SnCl2 can efficiently mediate the allylation of various aldehydes with allyl chloride or bromide, but not with allyl alcohol, in fully aqueous media. The yield of the reaction is very high (90–100%), and the reaction is operationally simple, environmental benign and easy to scale up.
Magnesium-Cadmium Chloride,
a Bimetallic Catalyst System for the Allylation of Aldehydes
with Allyl Bromide: An Efficient Protocol for the Synthesis
of Homoallylic Alcohols
A simple and efficient procedure for the allylation of aldehydes has been developed using the magnesium-cadmium chloride reagent system. This bimetallic catalytic system works well in a tetrahydrofuran-water solvent medium. A variety of aldehydes undergo smooth nucleophilic addition with allyl bromide to afford the corresponding homoallylic alcohols in excellent yields. All the reactions were performed
of α‐methylene‐γ‐lactones through the palladium(II)‐catalyzed lactonization of homoallylic alcohols with alkynamides has been reported. The hydroxyl group in the terminal olefins cooperates with the amide in alkynamides to promote the cyclization by suppressing the β‐H elimination. This process provides a route to construct naturally occurring biologically multifunctional α‐methylene‐γ‐lactones.
A highly efficient addition of allylic bromides to carbonyl compounds promoted by Cp2TiCl2(cat.)/Zn system
作者:Yu Ding、Gang Zhao
DOI:10.1016/s0040-4039(00)74734-4
日期:1992.12
Aldehydes or ketones reacted with allylic bromides in the presence of Cp2TiCl2(cat.)/Zn system at room temperature to give homo-allylic alcohols in high yields.