The synthesis of 5,6-dimethoxycyclopentano[h]-isoquinoline and derivatives

The synthesis of the previously unreported 5,6-dimethoxycyclopentano[h]isoquinoline ( 1 ) by way of a Pomeranz Fritsch ring closure of the diethyl acetal of 4,5-dimethoxy-7-indanylidene aminoacetaldehyde ( 3 ) is reported. Acetylation of the N-oxide of 1 yielded the corresponding N-acetyl-1-isoquinolone, which readily converted to the 1-isoquinolone on exposure to atmospheric moisture. Several diesters of the dihydroxy analog of 1 are reported.     

The total synthesis of coleophomones B, C, and D

Members of the coleophomone family of natural products all possess several intriguing and challenging architectural features, as well as exhibit unusual biological activity. They, therefore, constitute attractive targets for synthesis. In this Article, we describe the total synthesis of coleophomones B (2), C (3), and D (4). The highly strained and congested 11-membered macrocycle of coleophomones B (2) and C (3) was constructed using an impressive olefin metathesis reaction. Furthermore, both of the requisite geometric isomers of the Delta(16,17) within the macrocycle could be accessed from a common precursor, facilitating a divergence that lent the coleophomone B (2)/C (3) synthesis an unusually high degree of efficiency. The synthesis of coleophomone D (4) confirmed that it exists as a dynamic mixture of isomeric forms with a different aromatic substitution pattern from the other family members.