Cyclopropanes in Nicholas reaction: formation of spiroketals with a five-membered and a seven- or an eight-membered ring
作者:Chisato Mukai、Takahiro Kojima、Takamasa Kawamura、Fuyuhiko Inagaki
DOI:10.1016/j.tet.2013.05.056
日期:2013.9
The consecutive treatment of 5-hydroxy-1-pentynyl 2,2-disubstituted-cyclopropyl ketones with Co2(CO)8 and BF3·OEt2 produced the corresponding Co2(CO)6-complexed dioxaspiro[4.6] derivatives. The one-carbon homologated substrates also afforded dioxaspiro[4.7]. It was found that this procedure can be applied to the substrates with gem-disubstituents as well as a mono-aryl substituent on the cyclopropane
用Co 2(CO)8和BF 3 ·OEt 2连续处理5-羟基-1-戊炔基2,2-二取代的环丙基酮可得到相应的Co 2(CO)6络合的二氧杂螺[4.6]衍生物。一碳同系的底物也提供了二氧杂螺[4.7]。已经发现,该方法可以应用于具有宝石二取代基以及环丙烷上的单芳基取代基的底物,但是单烷基取代的环丙烷是不够的。