Synthesis of the Purported ent-Pochonin J Structure Featuring a Stereoselective Oxocarbenium Allylation

The synthesis of the alleged natural product pochonin J is presented. Key steps of this convergent synthesis include a chemoselective Wacker oxidation, and an Evans' anti-reduction of the resulting ketone. Upon ozonolysis, this intermediate undergoes a 6-exo-trig cyclization to give a hemiketal intermediate, the key oxocarbenium precursor. The construction of the alpha-C-glycoside subunit is highlighted by a mismatched oxocarbenium cation formation/allylation sequence. An olefin metathesis afforded the 14-membered macrolactone, and final oxidation provided the desired compound that does not spectroscopically correlate to the initially described natural product.