Unprecedented Grob-type fragmentation of 5-dioxolan-bicyclo[4.2.0]octan-2-ones into 3-(methoxycarbonylmethyl)cyclohexanones
摘要:
The unprecedented Grob-type fragmentations of 5-dioxolan-bicyclo[4.2.0]octan-2-ones 1 into 3-(methoxycarbonylmethtl)cyclohexanes 2 are described. This fragmentation, in combination with the allene photoannelation used to produce compounds 1, might constitute an indirect way for achieving: conjugate addition of methyl acetate; new syntheses of kaurane, stemarane and thirsiflorane diterpenes might be also envisaged from 2c and 2d. (C) 1997 Elsevier Science Ltd.