Substitutions lithium butyl cuprate

Substitution of alfylic sulfoxides. Lithium dimethyl cuprate and di-n-butyl cuprate react with allylic sulfoxides or sulfones mainly by y-substitution to give tri-substituted alkenes (equation I).15... 

The stannylcupration of alkynes has been widely studied. Reaction of alkynes with lithium bis(tributylstannyl) cuprate leads to r -2-(tri butyl stannyl) vinyl cuprates, which are synthetically equivalent to cis- 1,2-ethylene dianions. Addition of the tin-copper reagent across the triple bond occurs i>7/-stereospecifically, thus providing Z-vinylstannanes. Phenylacetylene reacts with the tin cuprate with a regiochemistry opposite to that of 1-decyne.294 The intermediate cuprates react well with the various electrophiles.295 For example, the reaction with ethylene oxide gives primary alcohols, and further treatment of their />-toluenesulfonates with butyllithium gives 1-substituted cyclobutenes (Equation (120)) 294... 

Lithium n butyl (phenylthio) cuprate has been used in nucleophilic substitution reactions of arenesulfonyl fluorides, al-lylic acetates, 9 BBN, propargyllc carbamates, and bromo-alkenes, as well as in nucleophilic additions to acetoxy-epoxides. It Is a good choice for 1,4-addItIon of an n-Bu group, having been used in 1,4 addition-elimination reactions of a-oxoketene dithloacetals and 3-halo-2-cycloalkenones, and in tandem vicinal dialkylation reactions of 5-methyleneoxa-zolones and alkynes. A typical example Is the use of the reagentin the stereospecific synthesis of (, -2-heptenoicacidfrom acetylene (eq 1). ... 

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