Alkynyl triazenes enable divergent syntheses of 2-pyrones
作者:Jin-Fay Tan、Carl Thomas Bormann、Kay Severin、Nicolai Cramer
DOI:10.1039/d1sc02583j
日期:——
The 2-pyrone motif occurs frequently in bioactive natural products and is appreciated as synthetic intermediates. However, only few methods allow for diversifying functional group modifications on this relevant heterocycle. The distinct properties of 1-alkynyl triazenes promote a smooth addition of propiolic acids across the triple bond. Addition of catalytic amounts of silver salt induces cyclization
Diels–Alder reaction of 2,3-bis(pinacolato)boryl-1,3-butadiene with electron-deficient alkenes and dimethyl acetylenedicarboxylate proceeded smoothly upon heating, giving rise to the corresponding ...
One stone two birds: construction of polysubstituted benzenes from the same starting material and precatalyst by switching the active sites of catalyst with different additives
作者:Chun Feng、Xin Wang、Bi-Qin Wang、Ke-Qing Zhao、Ping Hu、Zhang-Jie Shi
DOI:10.1039/c1cc15835j
日期:——
Two different tetrasubstituted benzenes were selectively constructed from the same starting materials by tuning the active sites of the Grubbs second generation catalyst (GC-II) with CuI or AgOTf as the additive.
Rhodium-catalyzed isomerization and alkyne exchange reactions of 1,4-dithiines occurred by cleavage of two C–S bonds. The 2,5- and 2,6-disubstituted 1,4-dithiins underwent isomerization reactions in toluene at 110 °C, providing equilibrium mixtures of isomers. At 150 °C, the reaction of 1,4-dithiins and dimethyl acetylenedicarboxylate gave unsymmetric 2,3-di(methoxycarbonyl)-1,4-dithiins and 2,3-d