Treatment of a novel 10-membered ring 1,6-diyn-3-ene compound 1 with alcoholic KOH solution gave isothiochromanol derivatives through a polar pathway. On the other hand, treatment of 1 with DBU in CCl4 afforded 8-chloro-isothiochromane derivatives through a free radical pathway.
The novel selenium mediated aromatization of a 1,6-diyn-3-ene system related to neocarzinostatin chromophore
Treatment of 1,6-diyn-3-ene system 1 with SeO2 caused a Myers type cyclization to produce a biradical 6 through an enyne–allene system 5 which was generated by an ene reaction of 1 with SeO2, in analogy with the case of neocarzinostatin chromophore.