https://www.selleckchem.com/pr....oducts/alantolactone
The detailed picture of bonding patterns suggests that the OPA formation in the Wittig mechanism can be better understood in terms of a two-stage one-step mechanism beyond molecular orbital considerations behind the traditionally accepted [2+2] cycloaddition proposal.Eight new polyhydroxanthones, penicixanthones A-H (1-8), including four monomers (1-4) and four dimers (5-8), were isolated from solid cultures of Penicillium purpurogenum SC0070. Their structures were elucidated by extensive spectroscopic analysis, X-ray single-cryst