2014 journal article
Total Synthesis of Alkaloid 205B
JOURNAL OF ORGANIC CHEMISTRY, 79(19), 9074–9085.
MeSH headings : Alkaloids / chemical synthesis; Alkaloids / chemistry; Catalysis; Heterocyclic Compounds, 3-Ring / chemical synthesis; Heterocyclic Compounds, 3-Ring / chemistry; Molecular Structure; Pyridines / chemical synthesis; Pyridines / chemistry; Stereoisomerism
TL;DR:
The synthesis features the use of an N-acylpyridinium salt reaction to introduce the first stereocenter and an unprecedented trifluoroacetic anhydride-mediated addition of an allylstannane to a vinylogous amide with complete facial selectivity.
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(Web of Science)
Source: Web Of Science
Added: August 6, 2018
Concise and highly stereocontrolled total syntheses of racemic and enantiopure frog alkaloid 205B (1) were accomplished in 11 steps from 4-methoxypyridines 6 and 7 in overall yields of 8 and 8%, respectively. The assembly of the core of the natural product relies on a stereoselective Tsuji–Trost allylic amination reaction and a ring-closing metathesis. The synthesis features the use of an N-acylpyridinium salt reaction to introduce the first stereocenter and an unprecedented trifluoroacetic anhydride-mediated addition of an allylstannane to a vinylogous amide with complete facial selectivity. Deoxygenation of the C4 ketone proved difficult but was accomplished via a modified Barton–McCombie reaction in the presence of a catalytic amount of diphenyl diselenide.