[reaction: see text] 9-Tosyl-3,4-dihydro-beta-carboline (1) reacted with a ketone in the presence of (S)-proline as a catalyst to give the corresponding addition product in good yield and high enantioselectivity. In the process, a small amount of water was found to affect the stereoselectivity of the products. The system was applied to reaction of compound 1 and 3-buten-2-one to give 3,4,6,7,12,12b-hexahydro-1H-indolo[2,3-a]quinolizin-2-one, which is a versatile precursor for the synthesis of some indole alkaloids.

Urea, which has both hydrogen bond acceptor and donor moieties, is an ideal structuref or as upramolecular synthon. Various supramolecules having ureido group(s) have been widelyd eveloped. This article summarizes recent developments of urea derivatives that exhibit various functions:i)supramolecular capsules that form discreteu reaurea intermolecular hydrogen bonds, ii)supramolecular polymers that form continuous urea-urea intermolecularh ydrogen bonds, iii)supramolecular gels that form continuous urea-urea intermolecular hydrogen bonds, iv) artificialh ost molecules based on the molecular recognition ability of the ureido group, and v) catalytic reactions developedb yu tilizing the molecular recognition ability of the ureido group.

[reaction: see text] 9-Tosyl-3,4-dihydro-beta-carboline reacted with 3-ethyl-3-buten-2-one in the presence of (S)-proline to give (3R,12bR)-3-ethyl-12-tosyl-3,4,6,7,8,9,10,11,12,12b-decahydro-1H-indolo[2,3-a]quinolizin-2-one in complete enantio- and diastereoselectivity. The compound thus obtained was readily transformed to ent-dihydrocorynantheol in three steps.

A stereoselective total synthesis of (-)-Renieramycin T (1t) from a key tetrahydroisoquinoline intermediate previously utilized in our formal total synthesis of Ecteinascidin 743 is described. The synthesis features a concise approach for construction of the pentacyclic framework using a Pictet-Spengler cyclization of bromo-substituted carbinolamine 17, which obviates the regioselectivity problem of the Pictet-Spengler cyclization. The results of cytotoxicity studies are also presented.

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