Journal ArticleDOI
Short, Enantioselective Total Synthesis of Okaramine N
TLDR
The first enantioselective total synthesis of a member of the okaramine family of bis-indole alkaloids, okaramines N, has been accomplished via intermediates 2-7, as outlined.Abstract:
The first enantioselective total synthesis of a member of the okaramine family of bis-indole alkaloids, okaramine N (1), has been accomplished via intermediates 2-7, as outlined. The N-prenylated derivative of (S)-tryptophan methyl ester (2) was coupled with Fmoc-protected N-tert-prenylated tryptophan (3) to form the amide 4 in 70% yield. Pd(II)-mediated cyclization/rearrangement, a key step in the synthesis, transformed 4 into the indoloazacine 5 (44%), which was deprotected and cyclized in a single step to give the hexacyclic diketopiperazine 6 (95%). In the following novel and key sequence, 6 was transformed into 1: (1) selective ene reaction with N-methyltriazolinedione, (2) photooxidation of the remaining tert-prenylated indole subunit to provide 7, and (3) thermal retroene reaction of 7 to afford okaramine N (70% from 6).read more
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C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals
TL;DR: This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.
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Palladium-catalyzed cross-coupling reactions in total synthesis.
TL;DR: In this Review, highlights of a number of selected syntheses are discussed, demonstrating the enormous power of these processes in the art of total synthesis and underscore their future potential in chemical synthesis.
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Recent developments in natural product synthesis using metal-catalysed C–H bond functionalisation
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Photochemical Reactions as Key Steps in Organic Synthesis
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