Organozinc reagents, conjugate

As 1,2-disubstituted triple bonds do not generally react with allylic organozinc reagents, conjugated terminal diynes underwent chemoselective allylzincation at the terminal alkyne moiety leading to allyl-substituted conjugated enynes (equation 138)173. 

Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents... 

In the presence of Lil, TMS-C1, and a catalytic amount of (CH3)2CuCNLi2, conjugate addition of functionalized organozinc reagents occurs in good yield. 

Organozinc reagents prepared from ultrasonic irradiation of organic halides with Li in the presence of ZnBr2 have recently been used for conjugate addition to a-enones [Eqs. (47) and (48)] (234,235). In the... 

Feringa and co-workers described the tandem addition-aldol cyclization protocol leading to the formation of 6,6-, 6,7-, and 6,8-annulated bicyclic systems (Scheme 68).39 Using Cu(n)-29 as catalyst and functionalized organozinc reagents as nucleophiles, the conjugate addition reaction followed by aldol cyclization can offer highly enantioselec-tive annulation products (up to 98% ee). This method can be used in the synthesis of carbocyclic compounds, such as steroids, terpenes, and other natural products. 

Feringa, B. L. Naasz, R. Imbos, R. Arnold, L. A. Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents. In Modem Organocopper Chemistry Krause, N. Ed. Wiley-VCH GmbH Weinheim, 2002 Chapter 7, pp 224—258. 

Copper-Catalyzed Conjugate Addition of Functionalized Organozinc Reagents to a,p-Unsaturated Ketones Preparation of Ethyl 5-(3-Oxocyclohexyljpentanoate. 

I 7 Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents Tab. 7.4. Conjugate additions to 2,5-cyclohexadienone monoacetals and ethers. 

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