Global desilylation

The acetate CR)-F was then converted to D, which was coupled with Garner s aldehyde C to give G. The building block A was prepared from G, and coupled with acid B to furnish H. Global desilylation of H afforded ceramide B (163) with 6R-configuration. Similarly, by employing (S )- as an intermediate, (2S,3R,4E,6S)-16y was synthesized. 

Reaction of acid 142 with alcohol 148 under Yamaguchi conditions followed by desilylation and esterification of acryloyl chloride with 149a furnished diene 150 (Scheme 6.27). RCM of 150 with Grubbs first-generation catalyst furnished the bis-lactone 151, which on global deprotection gave synthetic 152, whose spectral data was not concurrent with the reported data. Hence, the synthesis of 152 has distinctly specified that previously elucidated structure was incorrect for acremodiol (Scheme 6.27). 

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