Synthesis of new molecular scaffolds: 3-aza-7,9-dioxa-bicyclo[4.2.1]nonane (8-exo BTKa) and 3-aza-8,10-dioxa-bicyclo[5.2.1]decane (9-exo BTKa) carboxylic acids
Two classes of enantiopure molecular scaffolds were prepared, whose lactam structure formally derivesfrom the coupling between tartaricacid and β- or γ-ketoamines. We labelled these compounds as 8-exo and 9-exo BTKa, indicating the lactam size (8- and 9-membered ring, respectively). Starting from β- and γ-nitroketones, the synthesis involves the ketal formation by (R,R)-dimethyl tartrate. The subsequent
Starting from simple alkylidene oxindoles and nitroketones, a highly stereoselective methodology was developed for the synthesis of spiro-cyclopentaneoxindoles with four consecutive stereogenic centers. Using an organocatalytic cascade of Michael and aldol reactions in the presence of a chiral thiourea catalyst products were obtained in moderate to high yields and excellent enantioselectivities. Nitro, ester, and hydroxyl groups were introduced to the spiro ring, which could be used to facilitate further functionalization of the products.
MIYAKOSHI, TETUO;SAITO, SHOJIRO;KUMANOTANI, JU, CHEM. LETT., 1981, N 12, 1677-1678
作者:MIYAKOSHI, TETUO、SAITO, SHOJIRO、KUMANOTANI, JU
DOI:——
日期:——
MIYAKOSHI, TETSUO;SAITO, SHOJIRO, J. CHEM. SOC. JAP., CHEM. AND IND. CHEM., 1984, N 3, 458-462