Organocuprate reagent

Lautens examined the reaction of cuprates with [3.2.1] oxabicydic substrate 297 and found that the major reaction pathway is an SN2 addition-ring opening, but contrary to the usual syn opening, an anti addition of the nucleophile was observed. Minor products due to anti-SN2 addition to the olefin and addition to the carbonyl group were also obtained, Eq. 196 [222]. 

Higher order cuprates also ring opened unsymmetrical oxabicyclo [2.2.1] heptene 298 with good regioselectivity, Eq. 198 however, no selectivity was observed in the reaction with unsymmetrical substrates such as 299, Eq. 199 [202]. 

The reactivity of silylcuprates with oxabicyclic compounds was also examined [218, 223]. With oxabicyclo[2.2.1] compounds, addition and Peterson elimination to produce cyclohexadienes occurred as with silyllithium reagents, Eq. 200. 

However, with oxabicyclo[3.2.1] compounds, the product from addition to the olefin and trapping by the ketone were detected rather than the typical ring opening reaction, Eq. 201. 

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Fig. 8. Synthesis of PGE using an organocuprate reagent where DiBAL-H is diisobutylalurninurnhydride and R = (CH2 )g COOCH2 CH3.

The reaction of tert-alkyl Grignard reagents with carboxylic acid chlorides in the presence of a copper catalyst provides ieri-alkyl ketones in substantially lower yields than those reported here.4,14 The simplicity and mildness of experimental conditions and isolation procedure, the diversity of substrate structural type, and the functional group selectivity of these mixed organocuprate reagents render them very useful for conversion of carboxylic acid chlorides to the corresponding secondary and tertiary alkyl ketones.15... 

See Stemmier, T.L. Barnhart, T.M. Penner-Hahn, J.E. Tucker, C.E. Knochel, P. Bohme, M. Frenklng, G. J. Am. Chem. Soc., 1995, 117, 12489 for a discussion concerning the structure of organocuprate reagents. Solution compositions of Gilman reagents have also been studied. See Lipshutz, B.H. Kayser, F. Siegmann, K. Tetrahedron Lett., 1993, 34, 6693. 

Scheme 8.1 gives several examples of the use of coupling reactions of organocuprate reagents with halides and acetates. Entries 1 to 3 are examples of the... 

Carbocupration is one of the most useful carbometalations.504,508 Organocopper and organocuprate reagents add to the carbon-carbon triple bond to form new... 

Asymmetric induction in the conjugate addition of achiral residues to a,(3-unsaturated carbonyl compounds can be achieved with chiral ligand-modified organocuprate reagents. Early experiments, em-... 

A new method has been developed for the preparation of enantiomerically pure monosubstituted aziridines via the reaction of an A-to sy I - <9- to sy I az i ri d in e (48) with a primary organocuprate reagent.47 Attack occurs at the least substituted carbon atom of... 

Likewise, the reaction of iodonium salt 57 with lithium organocuprate reagents affords products of coupling 65 in good yields (Scheme 30) [54]. 

Scheme 11. Sequential use of the reagent directing o-DPPB group to control stereoselectivity in the course of hydroformylation and subsequent conjugate addition with organocuprates. Reagents and conditions (a) 0.7 mol% [Rh(CO)2acac], 2.8...

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