Total Synthesis of Uniflorine A, Casuarine, Australine, 3-<i>epi</i>-Australine, and 3,7-Di-<i>epi</i>-australine from a Common Precursor

Ritthiwigrom, Thunwadee; Willis, Anthony C.; Pyne, Stephen G.

doi:10.1021/jo902355p

Cited by 87 publications

(45 citation statements)

References 48 publications

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“…After many unsuccessful attempts to convert enone 19 to calystegine B 4 ( 20 ), we found the best method to achieve this was by first treatment of 19 with Pd(OH) 2 /H 2 in THF/H 2 O to reduce the double bond and remove one or two benzyl groups (as evident from ESIMS analysis). The crude reaction mixture was then treated with PdCl 2 /H 2 in THF/H 2 O to removed more benzyl groups, and finally treatment with PdCl 2 /H 2 in MeOH removed the remaining benzyl groups and the Boc group due to in situ formation of HCl 11d. The hydrochloride salt of 20 was deprotonated and purified by ion exchange chromatography using Amberlyst ® A‐26(OH) resin to give 20 in 51 % overall yield and in 92–95 % purity according to 1 H NMR analysis.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of Calystegine B₄

Moosophon¹,

Baird²,

Kanokmedhakul³

et al. 2010

Eur J Org Chem

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The total synthesis of calystegine B4 was achieved in 10 steps from (–)‐D‐lyxose by using a new synthetic strategy to obtain the requisite protected hydroxylated 4‐aminocyclohept‐2‐en‐1‐one without the problem of regioisomer formation that was a problem in the earlier synthesis of this natural product. The key steps included a Petasis–borono‐Mannich reaction and a ring‐closing metathesis reaction.

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Section: Resultsmentioning

confidence: 99%

Total Synthesis of Calystegine B₄

Moosophon¹,

Baird²,

Kanokmedhakul³

et al. 2010

Eur J Org Chem

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“…196 All these syntheses employed as key intermediate a chiral tetraol which arose from the asymmetric Petasis L-xylose with allylamine and (E)-styrene boronic acid. As shown in Scheme 1.116, the Petasis key product 70 was achieved in 92% yield as a single stereoisomer.…”

Section: Multicomponent Reactions Based On the Petasis Reactionmentioning

confidence: 99%

Asymmetric Domino Reactions Based on the Use of Chiral Substrates

2013

Asymmetric Domino Reactions

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This chapter updates the recent developments in asymmetric one-, two-, and multicomponent domino reactions which involve chiral substrates. It is divided into two sections, dealing successively with one- and two-component domino reactions, and with multicomponent domino reactions. The first section is subdivided into eight sections, describing domino reactions with an anionic primary step, domino reactions based on cationic sequences, domino reactions initiated by a pericyclic primary step, domino reactions based on carbene sequences, palladium-catalysed domino reactions, ruthenium-catalysed domino reactions, gold-catalysed domino reactions, and finally miscellaneous domino reactions. The second section of the chapter is subdivided into 10 sections, dealing with multicomponent reactions initiated by the Michael addition, multicomponent reactions based on the Hantzsch reaction, multicomponent reactions based on the Ugi reaction, multicomponent reactions based on the Strecker reaction, multicomponent reactions based on the Mannich reaction, multicomponent reactions initiated by an allylation reaction, multicomponent reactions based on the Passerini reaction, multicomponent reactions based on the Biginelli reaction, multicomponent reactions based on the Petasis reaction, and finally miscellaneous multicomponent reactions. The power and utility of these reactions are well illustrated by their application in the synthesis of a wide range of structurally diverse and complex chiral molecules.

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“…We have also employed the chiral 2,5-dihydropyrrole 6 towards the total synthesis of the pyrrolizidine alkaloids casuarine, australine, and 3-epi-australine through epoxidation of the double bond of the 2,5-dihydropyrrole 6 followed by diastereoselective ring-opening reactions with hydride and water (Scheme 3) [13].…”

Section: Synthesis Of Casuarine Australine and 3-epi-australinementioning

confidence: 99%