Catalytic crossed Michael cycloisomerization of thioenoates:: Total synthesis of (±)-ricciocarpin A

[GRAPHICS] Thioenoates are found to participate in highly chemoselective catalytic crossed Michael cycloisomerization with appendant aryl ketone and enoate partners to afford cyclopentene and cyclohexene products. This methodology has enabled a concise total synthesis of the potent molluscicide (+/-)-ricciocarpin A.