Direct, One-Step Synthesis of Condensed Heterocycles: A Palladium-Catalyzed Coupling Approach
作者:Farnaz Jafarpour、Mark Lautens
DOI:10.1021/ol061404k
日期:2006.8.1
[reaction: see text] A palladium-catalyzed one-stepsynthesis of fused aromatic heterocycles from bifunctional bromoenoates or bromoalkyl indoles and iodoarenes is reported. This method provides an efficient route to a wide variety of substituted polycyclic aromatic and heteroaromatic compounds from readily accessible starting materials.
Umpolung of Michael Acceptors Catalyzed by <i>N</i>-Heterocyclic Carbenes
作者:Christian Fischer、Sean W. Smith、David A. Powell、Gregory C. Fu
DOI:10.1021/ja058222q
日期:2006.2.1
N-Heterocycliccarbenes can catalyze beta-alkylations of a range of alpha,beta-unsaturated esters, amides, and nitriles that bear pendant leaving groups to form a variety of ring sizes. In this process, the nucleophilic catalyst transiently transforms the normally electrophilic beta carbon into a nucleophilic site through an unanticipated addition-tautomerization sequence.
Palladium-Catalyzed Sequential Alkylation−Alkenylation Reactions. Application to the Synthesis of 2-Substituted-4-Benzoxepines and 2,5-Disubstituted-4-Benzoxepines
The synthesis of 2-substituted-4-benzoxepines and 2,5-disubstituted-4-benzoxepines from aryliodides and bromoenoates is described. This methodology is based on a palladium-catalyzed aromatic substitution followed by an intramolecular Heck sequence. Under the reaction conditions (Pd(OAc)(2) (10 mol %), tri-2-furylphosphine (20 mol %), norbornene (2 equiv), Cs(2)CO(3) (2 equiv), CH(3)CN, 85 degrees