Benzofurans or Isochromenes via the Ring-Opening Cyclization of Cyclopropene Derivatives with Organolithiums
摘要:
A new and efficient approach to benzocycles from cyclopropene derivatives is described. Deprotection by organolithiums and subsequent ring-opening cyclization of the related 2-cyclopropenyl phenyl or benzyl acetates generated benzofurans and isochromenes in one pot.
Broad scope gold(<scp>i</scp>)-catalysed polyenyne cyclisations for the formation of up to four carbon–carbon bonds
作者:Zhouting Rong、Antonio M. Echavarren
DOI:10.1039/c7ob00235a
日期:——
The polycyclisation of polyenynes catalyzed by gold(I) has been extended for the first time to the simultaneous formation of up to four carbon–carbon bonds, leading to steroid-like molecules with high stereoselectivity in a single step with low catalyst loadings. In addition to terminal alkynes, bromoalkynes can also be used as initiators of polyene cyclisations, giving rise to synthetically useful