[56646-93-6] · C6H10CuLiO2 · Lithium Bis(1-methoxyvinyl)cuprate · (MW 184.65)
Physical Data: yellow mixture, prepared in situ.
Solubility: sol THF.
Preparative Methods: by the slow addition of a -40 °C solution of 1-Methoxyvinyllithium5,6 to a solution of purified Copper(I) Iodide in a Dimethyl Sulfide-THF mixture (1:4 mole ratio of CuI:Me2S) at -40 °C; stirring for 30 min gives a yellow mixture.3
Handling, Storage, and Precautions: air- and moisture-sensitive reagent prepared in situ. Use in a fume hood.
Lithium bis(1-methoxyvinyl)cuprate affords transfer of the 1-methoxyvinyl ligand, an acyl anion equivalent,7 via conjugate addition to a,b-alkenyl ketones (eq 1).3 This cuprate reaction is sensitive to the substitution patterns of the a,b-enone, especially at the C-3 and C-5 positions of cyclohexenone derivatives. The vinyl ether 1,4-adducts can be efficiently converted to either 1,4-diketones under dilute acidic conditions [0.025 N HCl/MeOH-H2O (4:1)] or 1,4-keto esters by ozonolysis in CH2Cl2-MeOH (9:1) at -60 °C.3
Lithium bis(1-methoxyvinyl)cuprate couples with Benzyl Bromide to afford a substitution product that, upon hydrolysis, yields 1-phenyl-2-propanone (eq 2). This reaction failed with 2-bromooctane.3
A lithium bis(1-methoxyvinyl)cyanocuprate reagent prepared from tetrakis(a-methoxyvinyl)tin reacts with Allyl Bromide to afford the coupling product in 60% yield.8
An allylic epoxide undergoes reaction with lithium bis(1-methoxyvinyl)cuprate to yield a substituted allylic alcohol (eq 3).9
g-Mesyl-a,b-enoates undergo reductive elimination with either lithium bis(1-methoxyvinyl)cuprate.BF3 or lithium bis(1-methoxyvinyl)cyanocuprate.BF3.2LiCl to afford b,g-enoates (eq 4) in excellent yield.4
Christopher W. Alexander
Emory University, Atlanta, GA, USA
Robert K. Boeckman, Jr.
University of Rochester, NY, USA