Intramolecular Cycloaddition of the Azomethine Ylides Derived from α-Amino Acids or Esters and 5-Oxo-6-heptenals or 4-Oxo-5-hexenals
作者:Shuji Kanemasa、Kenji Doi、Eiji Wada
DOI:10.1246/bcsj.63.2866
日期:1990.10
Intramolecularcycloadditions of the azomethine ylides bearing a carbonyl-activated olefinic moiety, generated from α-amino acids or esters and 5-oxo-6-heptenals or 4-oxo-5-hexenals, produce the stereoselective internal cycloadducts either to olefin or carbonyl dipolarophilic function with normal or inverse regioselectivity, depending upon the types of ylides as well as the intervening chain length
1-Alkenyl cyclopropylketones, when activated by cation-stabilizing substituents at the ring carbon or at the terminal carbon of the enone moiety, undergo polyphosphoric acid-catalyzed ring enlargement producing cyclopentanone or cyclohexenone derivatives. Similar acid-catalyzed ring opening of 1-alkenyl 2-phenoxycyclopropyl ketones offers a convenient and effective synthesis of 4-oxo-5-alkenals and