Efficient Synthesis of Functionalized Furans via Ruthenium-Catalyzed Cyclization of Epoxyalkyne Derivatives
作者:Ching-Yu Lo、Hongyun Guo、Jian-Jou Lian、Fwu-Ming Shen、Rai-Shung Liu
DOI:10.1021/jo020004h
日期:2002.5.1
Ruthenium catalyst TpRuPPh(3)(CH(3)CN)(2)Cl is found to effect the cyclization of epoxyalkynes to furans in the presence of Et(3)N. The reactions worked well for various epoxyalkynes with suitable oxygen and nitrogen functionalities with low loading of catalyst. It failed with disubstituted epoxyalkynes. The mechanism was elucidated by a deuterium labeling experiment that suggested that the mechanism
Synthesis of pyranose glycals via tungsten and molybdenum pentacarbonyl-induced alkynol cyclizations
作者:Frank E. McDonald、Hugh Y.H. Zhu
DOI:10.1016/s0040-4020(97)00366-9
日期:1997.8
The tungsten pentacarbonyl-induced cyclization of an acyclic alkynol substrate bearing protected oxygen and nitrogen functional groups provides the cyclic tungsten oxacarbene, which is readily converted into a pyranose glycal structurally related to the carbohydrate moieties of the pluramycin and vancomycin families of antitumor antibiotics. In addition a molybdenum-catalyzed cycloisomerization procedure