Cycloaddition reaction of schiff bases with ketenes generated by pyrolysis of 2-aryl-substituted 1,5,7-trioxaspiro[2.5]octane-4,8-diones
作者:Takashi Tsuno、Kosuke Kondo、Kunio Sugiyama
DOI:10.1002/jhet.5570430104
日期:2006.1
The α-oxo ketenes 6 which are generated by the pyrolysis of the 2-aryl-substituted 1,5,7-trioxaspiro[2.5]octane-4,8-diones 1, were reacted with Schiff bases 2 to give spiro compounds constructed between the β-lactam and 1,3-dioxolan-4-one; i.e., the 2,3,6-triaryl-2-aza-5,7-dioxaspiro[3.4]octane-1,8-diones 3 and 4. Hydrogenation of the mixture of 3a and 4a in the presence of catalytic amount of Pd-C
通过2-芳基取代的1,5,7-三氧杂螺[2.5]辛烷-4,8-二酮1的热解反应生成的α-氧代乙烯酮6与席夫碱2反应,得到在以下基团之间构筑的螺环化合物β-内酰胺和1,3-二氧戊环-4-酮;即2,3,6-三芳基-2-氮杂-5,7-二氧杂螺[3.4]辛烷-1,8-二酮3和4。在催化量的Pd-C存在下3a和4a混合物的氢化反应生成反式-2-苄氧基-1,4-二苯基-β-内酰胺-3-羧酸9。