This review covers the literature on simple indole alkaloids and those with a nonrearranged monoterpenoid unit from the beginning up to the end of 2004. Newly isolated alkaloids, structure determinations, total synthesis and biological activities are included.

This review covers the literature on simple indole alkaloids and those with a nonrearranged monoterpenoid unit. Newly isolated alkaloids, structure determinations, total syntheses and biological activities are included.

We have accomplished the first total synthesis of (+/-)-hinckdentine A (1). The key steps are m-CPBA oxidation of 2-arylindole followed by acid-mediated Mannich-type C-C bond formation of 2-hydroxyindolin-3-one, seven-membered ring closure, and regioselective tribromination.

The concise total synthesis of marine alkaloids, (-)-flustramines A and B, and (-)-flustramides A and B has been achieved through the domino olefination/isomerization/Claisen rearrangement (OIC) for highly enantioselective construction of the asymmetric quaternary carbon center and the chemoselective reduction-cyclization (RC) for pyrrolidine formation as key steps.

The electrochemical properties of lb and 2b were studied in THF and dimethyl sulfoxide (DMSO). Three reversible single electron reduction events are observed for lb in THF (-1.53, -2.04, and -2.61 V vs ferrocene/ferrocenium; -1.27 and -1.77 V in DMSO). The anion r-BuC^" is 0.67 V harder to reduce than in THF. For 2b, three reversible single electron reduction events are also observed (-1.01, -1.57, and -2.18 V in THF; -0.87 V in DMSO), making 2b 0.15 V harder to reduce than C60 (cf. (QHjJjCCso, which is 0.11 V harder to reduce than C609). Evidence is mounting911'12 that (QHs^CQo is not a fully "opened" structure as was originally proposed,9 which is in line with the similar reduction potential observed here for í-BuC^H.Protonation of the i-BuC^f anion can be quantitatively monitored by electrochemistry. From titration behavior using the acids saccharin (pATa = 4.0), 2,4-dinitrophenol (pK3 -5.1), and dichloroacetic acid (pKa = 6.4), a of 5.7 (±0.1) was determined for -BuQoH.4 Consistent with this, 2b can be deprotonated with «-Bu4N+CH3C02' in DMSO to form f-BuC60'. This ranks f-BuCegH as one of the strongest acids made up of only carbon and hydrogen.1314From the thermodynamic cycle employed by Bordwell,13 knowing this pAfa value and the f-BuC60*/f-BuC6(f reversible potential (-0.33 V vs ferrocene/ferrocenium: +0.33 V vs normal hydrogen electrode), we can calculate the C^-H bond dissociation energy to be 71 ± 2 kcal/mol in DMSO. This is on the low side of measured carbon-hydrogen bond strengths in organic hydrocarbon molecules. Supplementary Material Available; Details of the measurement of pK, for í-BuQqH and 13C NMR, NMR, mass spectral, and elemental analytical data for lb and 2b (8 pages). Ordering information is given on any current masthead page.