Rhodium- and palladium-catalysed formation of conjugated mono- and bis-exocyclic dienes. 5-Exo-trig versus 6-endo-trig cyclisations
作者:Ronald Grigg、Paul Stevenson、Tanachat Worakun
DOI:10.1039/c39840001073
日期:——
2-Bromo-1,6-dienes are catalytically cylised to give conjugated 5-membered bis-exocylic dines and 6-membered mono-exocyclic dienes by rhodium and palladium catalysts, the specificity for a 5- or 6-membered ring being a function of substrate, catalyst, and added base; 2-bromo-1,7-dienes cyclise regiospecifically to give 6-membered rings.
Zirconium-Mediated Intramolecular Coupling of Terminal Alkynes and Their Subsequent Carbonylation: Novel Synthesis of Seven- and Eight-Membered Heterocycles
作者:José Barluenga、Roberto Sanz、Francisco J. Fañanás
DOI:10.1002/chem.19970030820
日期:1997.8
AbstractThe development of a new method for the intramolecular coupling of terminal alkynes and for the synthesis of seven‐ and eight‐membered benzoheterocycles is reported. The key steps involve the generation of zirconocene‐alkyne complexes from 2‐bromoalkenes and the subsequent intramolecular carbometalation of olefins or acetylides. The 8‐unsubstituted zirconabicyclopentenes were carbonylated to afford unexpected products and allow access to polyfunctionalized molecules from simple starting materials.
GRIGG, RONALD;STEVENSON, PAUL;WORAKUN, TANACHAT, TETRAHEDRON, 44,(1988) N 7, C. 2033-2048