Copper-Mediated Selective Cross-Coupling of 1,1-Dibromo-1-alkenes and Heteronucleophiles: Development of General Routes to Heterosubstituted Alkynes and Alkenes
site-selective, double, or alkynylative cross-coupling, therefore providing divergent and straightforward entries to numerous building blocks such as bromoenamides, ynamides, ketene N,N-acetals, bromoenol ethers, ynol ethers, keteneO,O-acetals, or vinylphosphonates and further expanding the copper catalysis toolbox with useful and versatile processes.
Rh-Catalyzed aldehydic C–H alkynylation and annulation
作者:Maddali L. N. Rao、Boddu S. Ramakrishna
DOI:10.1039/c9ob02670c
日期:——
aldehydic C-Hbond alkynylation and annulation for the in situ synthesis of chromones and aurones are described. It involves the sequential aldehydeC-Hbond alkynylation of salicylaldehyde with in situ generated 1-bromoalkyne from 1,1-dibromoalkene followed by annulation. This protocol shows good functional group tolerance including aryl, alkenyl, alkyl and heteroaryl-1,1-dibromoalkenes. The steric/electronic
The first general synthetic approach to substituted [3]- and higher dendralenes is reported. Fifty-one mono- through to penta-substituted dendralenes carrying alkyl-, cycloalkyl-, alkenyl-, alkynyl-, aryl- and heteroaryl-substitutents are accessed, and the first (E)/(Z)-stereoselective syntheses of dendralenes are reported (twenty-eight examples). The approach involves twofold Pd(0)-catalyzed Negishi