Stereodefined Substituted Cyclopropyl Zinc Reagents from Gem-Bismetallics
摘要:
1,1- or n,n-Bismetallic reagents bearing a methoxymethyl ether in the gamma position undergo cyclization at room temperature to give monometalated, diastereoselectively substituted cyclopropanes, The nature of the substituents is crucial for this diastereoselection, a pi-chelation between one metal and a properly located unsaturation, as well as 1,2-strain, are proposed to explain the steric outcome of these reactions.
Stereodefined Substituted Cyclopropyl Zinc Reagents from Gem-Bismetallics
作者:Dov Beruben、Ilane Marek、Jean F. Normant、Nicole Platzer
DOI:10.1021/jo00113a032
日期:1995.4
1,1- or n,n-Bismetallic reagents bearing a methoxymethyl ether in the gamma position undergo cyclization at room temperature to give monometalated, diastereoselectively substituted cyclopropanes, The nature of the substituents is crucial for this diastereoselection, a pi-chelation between one metal and a properly located unsaturation, as well as 1,2-strain, are proposed to explain the steric outcome of these reactions.
A synthesis of the hexahydrobenzofuran portion of the avermectins I. Model studies
作者:Philip J. Parsons、Paul Willis、S.C. Eyley
DOI:10.1016/s0040-4020(01)88314-9
日期:1992.1
A tandem radical cyclisation has been used to construct a model for the synthesis of the hexahydrobenzofuran moiety present in the avermectins.