enantioselective Negishi cross‐coupling reaction, and the first arylation of α‐halo esters with arylzinc halides, are disclosed. Employing a cobalt‐bisoxazoline catalyst, various α‐arylalkanoic esters were synthesized in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield). A diverse range of functional groups, including ether, halide, thioether, silyl, amine, ester, acetal, amide, olefin
Roles reversed: An efficient cobalt‐catalyzed electrophilic amination of arylzinc reagents has been achieved. A variety of functionalized arylzincs and N‐chloroamines were coupled under mild conditions (see scheme). Both secondary and tertiary arylamines were obtained in moderate to excellent yields.
Cobalt-catalysed synthesis of highly substituted styrene derivatives via arylzincation of alkynes
作者:Martin Corpet、Corinne Gosmini
DOI:10.1039/c2cc36676b
日期:——
A new two-step procedure was developed by carbozincation of internal and terminal alkynes to synthesise highly functionalised vinylzinc bromides. Various tri and tetrasubstituted alkenes were prepared in moderate to good yields under mild reaction conditions in a stereo-selective manner. This methodology represents an interesting alternative to previously known methods.