Catalytic One-Pot Synthesis of Trisubstituted Allenes from Terminal Alkynes and Ketones
作者:Qi Liu、Xinjun Tang、Yujuan Cai、Shengming Ma
DOI:10.1021/acs.orglett.7b02443
日期:2017.10.6
one-pot synthesis of trisubstituted allenesfrom readily available terminal alkynes and ketones is realized. A wide range of trisubstituted allenes may be synthesized efficiently via this method. Preliminary mechanistic studies revealed that CuI and Ti(OEt)4 are in charge of the formation of propargylic amine, while ZnBr2 is responsible for the transformation from propargylic amine to allene.
Regio- and stereoselective synthesis of Z-vinylic tellurides from propargylic alcohols: a route to chiral Z-enynes
作者:Cristiano Raminelli、Nathalia C. da Silva、Alcindo A. Dos Santos、André L.M. Porto、Leandro H. Andrade、João V. Comasseto
DOI:10.1016/j.tet.2004.10.087
日期:2005.1
tert-Butyldimethylsilyl ethers of propargylic alcohols are hydrotellurated regioselectively to give 1,2-Z-vinylic tellurides. Enantiomerically pure propargylic alcohols give enantiomerically pure vinylic tellurides, which are coupled with alkynes under Pd catalysis to give enantiomerically pure allylic enynols.
The synthesis of the styryl lactone Leiocarpin C has been achieved in a highly stereoselective manner using Jacobsen’s kinetic resolution, Sharpless asymmetric epoxidation and Sharpless asymmetric dihydroxylation as key steps. This is the first totalsynthesis of Leiocarpin C, and thus establishes for the first time the absolute stereochemistry of this natural product.