Novel “one-pot” preparation of tetrahydrobenzodipyran-4-ones. Application to the synthesis of precocene analogues with condensed dihydropyran rings
作者:F. Camps、O. Colomina、J. Coll、A. Messeguer
DOI:10.1016/0040-4020(82)85025-4
日期:1982.1
A novel one-pot preparation of tetrahydrobenzodipyran-4-ones 5 and 6 involving the sequential condensation of resorcinols 7 with 3,3-dimethylacrylic acid (8) and 1,3-methylbutane (10) in the presence of methansesulphonic acid (which acts as solvent and catalyst) and further conversion of tetrahydrobenzodipyran-4-ones to the corresponding dihydrobenzodipyrans 3 and 4, which are precocene analogues,
Regioselective synthesis of substituted pterocarpans and pterocarpenes. Lewis acid Ti (IV) promoted formal (3+2) cycloaddition reactions.
作者:Modachur G. Murugesh、Kandasamy Subburaj、Girish K. Trivedi
DOI:10.1016/0040-4020(95)01052-1
日期:1996.2
A synthesis of novel pterocarpans (8a–e, 10a–c and 11a–e) and pterocarpenes (7a–d and 9a–c) has been carried out. This method involves the Lewis acid Ti (IV) promoted formal (3+2) cycloaddition reaction of 2-alkoxy-1,4-benzoquinones (6a–c) with appropriately substituted 2H-chromenes (1a–b, 2a–b and 5) at −78°C.