γ-Selective allylic substitution reaction with Grignard reagents catalyzed by copper N -heterocyclic carbene complexes and its application to enantioselective synthesis
The reaction of allylic compounds with alkyl Grignard reagents in the presence of a catalytic amount of copper N-heterocyclic carbene (NHC) complexes proceeded predominantly in an SN2′ reaction pathway to give γ-substituted product in excellent yield. The method was applied to asymmetric reaction by using optically active NHC ligands.
The cross-couplingreaction of allylic carbonates with organosilanes was found to proceed without fluoride ion activation under mild conditions by using a coordinatively unsaturated palladium complex as a catalyst. The reaction was assumed to proceed through an allylpalladium alkoxide derived from the allylic carbonate substrate and a palladium(0) species, the alkoxo ligand activating the organosilicon
Alkenylfluorosilanes smoothly underwent cross-coupling reaction with allylic carbonates in the presence of a palladiun catalyst and in the absence of fluoride ion to give 1,4-dienes in good yields with retention of configuration.
Synthesis of α-Amino-γ-lactams through Pd-Catalzed Intramolecular Allylic Alkylation of Sarcosine Allyl Amides
作者:Sarah Thies、Uli Kazmaier
DOI:10.1002/ejoc.201301659
日期:2014.3
N-Protected amino acid allyl amides with an allylic leaving group can be used as substrates in palladium-catalyzed allylic alkylation. Whereas intermolecular allylations proceed with excellent yields under standard conditions for enolate reactions, the intramolecular version is not a trivial issue. N-Protected glycine amides preferentially form piperidinones through N-allylation, but the corresponding