Cycloaddition of phenyl vinyl sulphone to 3-methoxy-16-methylestra-1,3,5(10),14,16-pentaen-17-yl acetate: synthesis of 14-functional ised 19-norpregnane derivatives
作者:James R. Bull、Karl Bischofberger
DOI:10.1039/p19910002859
日期:——
Diets–Alder reaction of 3-methoxy-16-methylestra-1,3,5(10),14,16-pentaen-17-y1 acetate 3 with phenyl vinylsulphone affords three 14,17-cycloadducts; the two major products (ca. 37% each) are the regioisomers derived from endo addition on the β-face, whereas the minor product (ca. 14%) is the endo isomer of meta-directed attack on the α-face. Sequential reductive desulphonylation, hydroxylation, and