Effect of Additives on the Stereochemical Integrity and Reactivity of α-Alkoxycarbonyl Alkenylcopper Intermediates. Optimal Conditions for the Synthesis of Isomerically Pure Tetrasubstituted Alkenes
作者:Na Zhu、Dennis G. Hall
DOI:10.1021/jo034465u
日期:2003.7.1
A systematic study on the effect of additives on the isomerizability of 1-alkoxycarbonyl alkenylcopper(I) intermediates revealed that the lithium chelator 12-crown-4 is significantly more efficient than HMPA at retarding isomerization. On the other hand, 12-crown-4 alone is unable to promote effective coupling with alkyl halides. The combination of 12-crown-4 and a reduced amount of HMPA, however,
Iron-Catalyzed Stereoselective Cross-Coupling Reactions of Stereodefined Enol Carbamates with Grignard Reagents
作者:Ana Cristina Parra Rivera、Raymond Still、Doug E. Frantz
DOI:10.1002/anie.201601899
日期:2016.6.1
A practical and highly stereoselective iron‐catalyzedcross‐coupling reaction of stereodefined enol carbamates and Grignard reagents to yield tri‐ and tetrasubstituted acrylates is reported. A facile method for the stereoselective generation of these enol carbamates has also been developed.