p. 2182 - 2184
(2003){(4R,6R)-6-Isopropyl-5-[(E)-(R)-2-methoxymethyl-pyrrolidin-1-ylimino]-2,2-dimethyl-[1,3]dioxan-4-yl}-acetic acid tert-butyl ester
((4R,6R)-6-Isopropyl-2,2-dimethyl-5-oxo-[1,3]dioxan-4-yl)-acetic acid tert-butyl ester
((4R,6R)-6-Isopropyl-2,2-dimethyl-5-methylene-[1,3]dioxan-4-yl)-acetic acid tert-butyl ester