Benzilic acid rearrangement-type reaction of physalins to neophysalins. Structural revision of one of the dehydration products of physalin A

Abstract The previously proposed structure of an acid-induced dehydration product of physalin A, a 13,14-seco-16,24-cyclosteroid, is revised as having a new carbon skeletal structure named neophysalin. The reaction from physalins to neophysalins proceed via a kind of the benzilic acid rearrangement.