Addition of polyfunctional and pure (E or Z) alkenylcopper and arylcopper compounds to alkylidenemalonates
作者:G�rard Cahiez、Patricia Venegas、Charles E. Tucker、Tahir N. Majid、Paul Knochel
DOI:10.1039/c39920001406
日期:——
Polyfunctional and stereochemically pure (E) or (Z) alkenylcopper reagents have been generated by carbocupration of terminal alkynes or by an iodine–lithium exchange reaction and have been found to add to various diethyl alkylidenemalonates, affording γ,δ-unsaturated esters in excellent yields.
Preparation of highly functionalized magnesium, zinc, and copper aryl and alkenyl organometallics via the corresponding organolithiums
作者:Charles E. Tucker、Tahir N. Majid、Paul Knochel
DOI:10.1021/ja00036a060
日期:1992.5
Preparation of polyfunctional olefins and allenes using 1,1-bimetallics of zinc and zirconium
作者:Charles E. Tucker、Bjoern Greve、Wolfram Klein、Paul Knochel
DOI:10.1021/om00013a020
日期:1994.1
The hydrozirconation of various alkenylzinc halides with Cp2Zr(H)Cl in dry dichloromethane provides 1,1-dimetalloalkanes of zinc and zirconium which react with aldehydes, providing (E)-alkenes with good to excellent stereoselectivity (up to 98% E). The reaction tolerates the presence of a wide range of functionalities in the dimetallic species as well as in the aldehyde, allowing the preparation of functionalized olefins. Ketones can also be olefinated by these reagents. However, only a moderate stereoselectivity is observed. The hydrozirconation of alkynylzinc halides with CP2Zr(H)Cl gives 1,1-dimetalloalkenes of zinc and zirconium which react with aldehydes, affording allenes. The olefination of alpha,beta-unsaturated aldehydes provides a short access of 1,2,4-trienes.