Asymmetric synthesis of cytospolides C and D through successful exploration of stereoselective Julia-Kocienski olefination and Suzuki reaction followed by macrolactonization

Abstract

Abstract Asymmetric total synthesis of two naturally occurring nonenolides cytospolides C (3) and D (4) was accomplished through successful exploration of stereoselective Julia-Kocienski (JK) olefination reaction for the construction of the required E-olefinic geometry (C4-C5) present in the target molecule. In an alternative approach Suzuki cross coupling reaction of an E-vinylic bromide and an alkylborane species was also efficiently applied to access the macrolactonization precursor. Late stage lactonization through Mitsunobu cyclization afforded the target molecules in good yield.