ABSTRACT
A handsome couple: Through the use of the simple Pd catalyst [Pd(tmpp)(2)Cl(2)] (tmpp = tris(2,4,6-trimethoxyphenyl)phosphine) and THF/DMF as solvent, various aryl-, heteroaryl-, benzyl- and alkylaluminum reagents can be readily cross-coupled with aryl or heteroaryl iodides, bromides, and nonaflates, and in special cases even with chlorides and triflates. This cross-coupling tolerates free NH(2) groups, aldehydes, ketones, esters, and nitro functions.
Subject(s)
Aluminum/chemistry , Organometallic Compounds/chemistry , Organometallic Compounds/chemical synthesis , Palladium/chemistry , Catalysis , Molecular StructureABSTRACT
In-sertion of metal: Catalytic amounts of InCl(3) allow the insertion of aluminum and zinc into aromatic 1,2-dibromides or 1,2-bromotriflates. These 1,2-dimetallic species can undergo Cu or Pd-catalyzed acylations, allylations, or cross-couplings.
ABSTRACT
The reaction of commercial Al-powder (3 equiv) and InCl(3) (1-5 mol %) with benzylic chlorides provides various functionalized benzylic aluminum sesquichlorides under mild conditions (THF, 20 °C, 3-24 h) without homocoupling (<5%). These new benzylic organometallics reacted smoothly with various electrophiles (Pd-catalyzed cross-couplings, or Cu-mediated acylations, allylations, or 1,4-addition reactions). Electron-poor benzylic chlorides or substrates prone to Wurtz coupling can be converted to benzylic zinc compounds by the reaction of Al-powder in the presence of ZnCl(2).
ABSTRACT
Alkyl bromides bearing various functional groups are smoothly converted to functionalized alkylzinc reagents by the direct insertion of magnesium in the presence of LiCl and ZnCl(2).
