Copper preformed lithium

The reduction of a solution of a trialkylphosphine copper(I) iodide complex (CuIPR ) with preformed lithium naphthalide (LiNp) in THF or DME under argon was found to give a more reactive copper species, which will undergo oxidative addition with a variety of organic substrates at room... 

Reactions of halogen-stabilized carbenoids with imines have been carried out using preformed lithium species e.g. equation or via a carbenoid generated from diiodomethane utilizing zinc-copper... 

Reactions of halogen-stabilized carbenoids with imines have been carried out using preformed lithium species (e.g. equation 36),or via a carbenoid generated from diiodomethane utilizing zinc-copper couple (Simmons-Smith conditions). A steteospecific ring closure is observed after the addition of lithiodichloromethane to a benzaldimine (equation 37).The addition of lithiochloro(phenylsulfon-yl)methane to aromatic imines affords 2-phenylsulfonyl-substituted aziridines, which can be deproton-ated and alkylated in excellent yield (Scheme 20). 

A new, highly reactive copper species made from the reduction of copper(I) complexes with two equivalents of preformed lithium naphthalenide leads to a reagent that behaves chemically as a formal copper anion solution [20]. Lithium naphthalenide provides a suitable reducing agent for a variety of metals and offers unique advantages over other techniques used in metal activation, such... 

Li(0) (4.2 mmol) and naphthalene (4.6 mmol) in freshly distilled THF (5 ml) were stirred at room temperature under an argon atmosphere for 2 h. To this dark-green preformed lithium naphthalenide solution (-78 C), lithium 2-thienylcyanocuprate (0.25 M, 16 ml, 4.0 mmol) was added via a syringe. The solution of activated copper was used after it was stirred at -78°C for 0.5 h. For... 

In 1952 Gilman and co-workers reported that the yellow, ether-insoluble methylcopper dissolved to give a clear colorless solution on addition of a further equivalent of methyllithium 119). The new copper compound, of composition LiCu(CH3)2, is an ate complex now usually known as lithium dimethylcuprate. Mixed cuprates can be prepared from a preformed organocopper compound, RCu, and a lithium reagent 147, 259, 298, 301). 

Methoxyallene has previously been used to prepare acetylenes via its reaction with Grignard reagents, in the presence of copper(i) halides.The use of preformed dialkylcuprates, however, gave the vinyl ethers instead. The E Z ratio varied with the substituent but it is difficult to explain why the difference is observed.Methoxyallene has also been converted into its vinyl anion and used in the synthesis of dihydrofurans and furans in an analogous way to ordinary vinyl ethers.Similarly allenic cuprates have been prepared and used in the synthesis of allenes and allenic pheromonessome examples are outlined in Scheme 58. The addition of lithium dimethylcuprate to allene phosphine oxides and allenic ketones was interpreted in terms of a 1,2- rather than a 1,4-addition process, in contrast to a/3-unsaturated... 

---