Lithium diphenylcuprate, reaction with

Reaction of lithium diphenylcuprate with optically active 2 bromobutane yields 2 phenylbu tane with high net inversion of configuration When the 2 bromobutane used has the stereostruc ture shown will the 2 phenylbutane formed have the R or the S configuration" ... 

The viabihty of this synthetic approach to the introduction of a carboxylic acid fimction at C2 has been demonstrated in two ways. Following lithium diphenylcuprate addition to 564, the newly introduced phenyl group is subsequently degraded by ozonolysis to provide 567. Alternatively, reaction of 564 with diethylaluminium cyanide in toluene gives 568 which is also conveniently transformed into 567... 

Researchers at Merck have studied the synthesis of the simple caibapenem system (94) through Wittig cyclization of the keto ylide (93). This interesting precursor was prepared directly from the thiol ester (92) by reaction with lithium dimethylcuprate or magnesium diphenylcuprate (Scheme 34). ... 

This is a very general reaction in that primary, secondary, and tertiary alkyl halides react with primary, secondary, or tertiary organocuprates. The halide can be a chloride, a bromide, or an iodide, but iodides are more reactive than bromides, which are more reactive than chlorides. Another example is the reaction of 49 with lithium diphenylcuprate to give 50. The reaction of alkyl halides and organocuprates is the preferred method for coupling an alkyl halide to an organometallic compound. Many different hydrocarbons can be prepared. 

Whitesides et al. (1969a) have made a detailed study of the coupling reaction and found that (+)-(/ )-2-bromobutane enters into the reaction with lithium diphenylcuprate with predominant inversion (84-92%) of stereochemistry. Alkyl tosylates can also be used as substrates (Whitesides et al.. 

Treatment of -caprolactone with 7V,7V-bis(trimethylsilyl)lithium amide and then with A-phenyl triflimide affords 2-triflyloxy-2-hexenolide (22). The latter is obtained in 89% yield <89CL1313> and can be regarded as a key intermediate in the syntheses of diverse 2-substituted 4,5,6,7-tetra-hydrooxepines. For instance, reactions of (22) with lithium dialkyl- or diphenylcuprates result in 2-butyl-substituted derivatives (23 R = Aik, Ph) <89CL1313>, while analogous interaction with hexa-methyldistannane gives 2-trimethylstannyl-4,5,6,7-tetrahydrooxepin (23 R = SnMcj) <91SL197>. 

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