Vicinal Dianion of Triethyl Ethanetricarboxylate: Syntheses of (±)‐Lichesterinic Acid, (±)‐Phaseolinic Acid, (±)‐Nephromopsinic Acid, (±)‐Rocellaric Acid,and (±)‐Dihydroprotolichesterinic Acid

The vicinal dianion 2 derived from triethyl ethanetricarboxylate reacted regioselectively with aldehydes and ketones at C(β) to provide paraconic acid derivatives 5a – f in moderate to high yields as mixtures of diastereoisomers. The paraconic acid derivatives 5e and 5f were utilized as the starting materials for the syntheses of (±)‐lichesterinic acid ( 12 ), (±)‐phaseolinic acid ( 13 ), (±)‐nephromopsinic acid ( 14 ), (±)‐rocellaric acid ( 15 ), and (±)‐dihydroprotolichesterinic acid ( 16 ).