1247879-97-5Relevant academic research and scientific papers
Synthesis of the C20-C32 tetrahydropyran core of the phorboxazoles and the C22 epimer via a stereodivergent Michael reaction
Clarke, Paul A.,Ermanis, Kristaps
, p. 5550 - 5553,4 (2012)
A stereoselective synthesis of the C20-C32 tetrahydropyran core of the phorboxazoles has been achieved in only seven steps and in a 31% overall yield. The C22 epimer was also synthesized. The key step was a silyl ether deprotection/oxy-Michael cyclization. When this step was conducted under Bronsted acid conditions, the C20-C32 core was formed with the desired 2,6-cis-stereochemistry. However, when the silyl ether deprotection/oxy-Michael cyclization was conducted under fluoride conditions buffered with acetic acid, the C22 epimer of the core was the sole product.
