STEREOCHEMICAL FEATURES OF CYCLOADDITION OF HETEROAROMATIC<i>N</i>-YLIDES. SELECTIVE PARTICIPATION OF THE ANTI AND SYN YLIDES
作者:Otohiko Tsuge、Shuji Kanemasa、Shigeori Takenaka
DOI:10.1246/cl.1985.355
日期:1985.3.5
In the cycloaddition of heteroaromatic N-ylides to symmetrically substituted trans olefins, the anti ylide exclusively participates if the ylide is carbonyl-stabilized, while the syn ylide does if it has a substituent of non-carbonyl type. The cycloadducts isomerize into thermodynamically more stable isomers through a retro reaction.
Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic<i>N</i>-Ylides with Symmetrically Substituted cis and trans Olefins
作者:Otohiko Tsuge、Shuji Kanemasa、Shigeori Takenaka
DOI:10.1246/bcsj.58.3137
日期:1985.11
Stereochemistry of the cycloadditions of twenty-four heteroaromatic N-ylides with several symmetrically substituted cis and trans olefins has been investigated. Cyclic and acyclic cis olefins cycloadd to the and form of the ylides in a highly endo-selective manner giving almost quantitative yields of stereospecific endo 3+2 cycloadducts. N-Ylides stabilized with a substituent of carbonyl type react