No products arising from y Michael addition were observed as evidenced by the crude NMR spectrum. Notably, no elimination of the tetrahydropyranyloxy group could be detected. Compound 5 was clearly a mixture of stereoisomers. However, each isomer should be convertible to the desired product. Acid-catalyzed removal of the alcohol protecting group afforded 6. Several reaction conditions were studied for the transformation of alcohol 6 ...
