During an synthetic expedition towards a unique sesterterpenoid Astellatol by Xu and coworkers, an attempt to deprotect a TMS-protected alcohol with TBAF led to a unexpected rearrangement of the starting material instead of the desilylated alcohol.
Propose a mechanism for this transformation and an explanation for the product’s stereochemistry.
For reference:
Zhao, N., Yin, S., Xie, S., Yan, H., Ren, P., Chen, G., Chen, F. and Xu, J. (2018).
“Total Synthesis of Astellatol.”
Angewandte Chemie International Edition, 57(13), 3386–3390.
doi:10.1002/anie.201800167