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Total synthesis
About: Total synthesis is a research topic. Over the lifetime, 25578 publications have been published within this topic receiving 489319 citations.
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123 citations
TL;DR: The first total synthesis of tricyclic marine alkaloids (±)-fasicularin (2) and lepadiformine (5) was accomplished in this paper.
Abstract: The first total synthesis of tricyclic marine alkaloids (±)-fasicularin (2) and (±)-lepadiformine (5) was accomplished. The key common strategic element for the synthesis is the stereocontrolled intramolecular hetero-Diels−Alder reaction of an N-acylnitroso moiety to an exocyclic diene with or without bromine substitution to control the syn-facial or anti-facial selectivity, respectively, leading to the trans- or cis-fused decahydroquinoline ring systems 21 or 39 involving the simultaneous introduction of the nitrogenated quaternary center in a single step. On further elaboration of the six-membered or five-membered ring A, the trans-fused adduct 21 provided either (±)-fasicularin (2) or (±)-lepadiformine (5). The hydrochloride salt of synthetic (±)-5 was found to be identical with the isolated natural sample of lepadiformine; however, the tricyclic amino alcohol 4 having the proposed structure of lepadiformine in a nonzwitterionic form, derived from the cis-fused adduct 39, was found to be different from...
122 citations
TL;DR: Silver nanoparticles are reported as solid, recyclable catalysts for Diels-Alder cycloadditions of 2'-hydroxychalcones and dienes in high yield and turnover number and the total synthesis of the cytotoxic natural product panduratin A employing a highly electron-rich dienophile and Lewis acid sensitive diene.
Abstract: Metal nanoparticles are currently being employed as catalysts for a number of classical chemical transformations. In contrast, identification of novel reactions of nanoparticles, especially toward the synthesis of complex natural products and derivatives, is highly underdeveloped and represents a bourgeoning area in chemical synthesis. Herein, we report silica-supported silver nanoparticles as solid, recyclable catalysts for Diels-Alder cycloadditions of 2'-hydroxychalcones and dienes in high yield and turnover number. The use of silver nanoparticle catalysts is further demonstrated by the total synthesis of the cytotoxic natural product panduratin A employing a highly electron-rich dienophile and Lewis acid sensitive diene.
122 citations
TL;DR: The first highly enantioselective organocatalyzed carbo [3 + 3] cascade cycloaddition of α,β-unsaturated aldehydes is reported in this paper.
122 citations
TL;DR: The polycyclic, tryptamine-derived indole alkaloids communesins A and B were first isolated by Numata and co-workers in 1993 from a marine fungus of the Penicilliun genus and demonstrated potent inhibition of murine lymphocytic leukemia tumor cell proliferation in preliminary studies.
Abstract: The polycyclic, tryptamine-derived indole alkaloids communesins A and B (1 and 2, respectively) were first isolated by Numata and co-workers in 1993 from a marine fungus of the Penicilliun genus. Their spectroscopically established structures include two contiguous quaternary centers and two fused bicyclic aminals. Communesins A and B both demonstrated potent inhibition of murine lymphocytic leukemia tumor cell (P-388) proliferation in preliminary studies, with ED50 values (50% effective doses) of 3.5 and 0.45 mgmL , respectively. In the following years, six other members of this family, namely communesins C–H (3–8) have been isolated from different marine sources, with most having shown significant antileukemic and insecticidal activities. The remarkable biological properties and fascinating structures of these molecules have stimulated considerable interest in the synthetic community. In the past few years, numerous elegant methods for assembling their core structures and three total syntheses of communesin F have been disclosed.
122 citations