Recent progress in the chemistry of indole alkaloids and mould metabolites

Recent progress in the chemistry of the monoterpenoid indole alkaloids

“…This would appear to be the first example of the successful use of orthomalonates in Claisen ester rearrangements. By use of methods previously published, 20, 21 Lounasmaa and his co-workers have prepared 22 the four possible deformylgeissoschizines 21, together with their N a tertbutoxycarbonyl (N a -Boc) derivatives, their cis N b -oxides, and two of their trans N b -oxides. The predominant conformations of these compounds were determined from their NMR spectra, full details of which were given, together with assignments.…”

“…This oxidative cyclization was not entirely regiospecific, since minor amounts of condyfoline 133 were also obtained (Scheme 21). 58 The synthesis 59 of norfluorocurarine and akuammicine is remarkably brief, and begins with the alkylation of the arylhexahydroindolone derivative 134, previously prepared, 21 by means of (Z)-1-bromo-2-iodobut-2-ene. Treatment of the product 135 with nickel bis(cyclooctadiene) in the presence of lithium cyanide effected the closure of ring D (formation of the 15,20-bond), and brought about the reductive cyclization of the -(o-nitrophenyl)ketone grouping, to give the pentacyclic base, ( )-didehydrotubifoline 136 in a single step (Scheme 22).…”

“…The stems of Nothapodytes foetida, from Taiwan, contain two new alkaloids, nothapodytines A and B, which are presumably derived from camptothecin by decarboxylative fission of ring E. Nothapodytine B has the structure 297 and nothapodytine A is its 9-methoxy derivative 298 127 Details of the synthesis of camptothecin by Curran et al 21 have been published, 128 and an improved, second generation synthesis has also been developed. 129 In this new synthesis, and in contrast to the strategy adopted in the first synthesis, the lactone ring was built up before the completion of rings A-D.…”

Asymmetric Total Synthesis of (+)-21-epi-Eburnamonine Via a Photocatalytic Radical Cascade Reaction

“…The eburnamine-vincamine indole alkaloids are a large group of natural products occurring in the plant family Apocynaceae (For selected reviews, see: [1][2][3][4][5][6][7][8]). Featuring the fused-pentacyclic skeleton with multiple continuous stereocenters, this compound class has played an important role in natural product chemistry owing to their diverse structures (For selected reviews, see: [1][2][3][4][5][6][7][8]) and medical importance in cell multiplication, cardiovascular system, and brain functions [9,10]. During the past few decades, the continuing interests in this family regarding either the synthesis or the pharmacological activities have led to abundant research results.…”

(+)- and (−)-Spiroreticulatine, A Pair of Unusual Spiro Bisheterocyclic Quinoline-imidazole Alkaloids from the South China Sea Sponge Fascaplysinopsis reticulata

“…13 A plausible biogenetic pathway for 1 could be proposed as shown in Scheme 1. The biosynthesis of (+)-1 and (−)-1 were assumed by way of the indispensable coisolated indole-3-carboaldehyde (intermediate A, 2) and 3′-deimino-3′-oxoaplysinopsin (intermediate C, 3). The conversion from L-tryptophan into indole-3-carboaldehyde could be carried out by a homologue of NokA.…”