A Straightforward Synthetic Entry to Cleavamine-Type Indole Alkaloids by a Ring-Closing Metathesis−Vinyl Halide Heck Cyclization Strategy

Bennasar, M.‐Lluïsa; Solé, Daniel; Zulaica, Ester; Alonso, Sandra

doi:10.1021/ol200437k

Cited by 31 publications

(25 citation statements)

References 33 publications

(15 reference statements)

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“…However, synthesis of the strained phenanthro-annulated nine-membered-ring azonane motif in 2 presented a challenge. Traditional strategies for the preparation of this core architecture involve direct methods such as N-substitution reactions 24 (e.g., Mitsunobu reaction and alkylation), lactamization 25 , and ring closure metathesis 26 . Indirect methods involving ring expansion 27 – 29 via fragmentation of azabicycles offered another option, although syntheses using such methods tend to be complex.…”

Section: Resultsmentioning

confidence: 99%

Total synthesis of the reported structure of 13a-hydroxytylophorine

Zhang

et al. 2017

Sci Rep

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The first total synthesis of the reported structure of 13a-hydroxytylophorine was accomplished. The key step was an unprecedented NaBH4-promoted one-pot reductive cyclization cascade that efficiently yielded a hydroxyl azonane intermediate. The indolizidine framework was obtained by means of oxidation and a subsequent unexpected protecting-group migration. This total synthesis revealed that the reported structure of the naturally isolated compound is incorrect.

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Section: Resultsmentioning

confidence: 99%

Total synthesis of the reported structure of 13a-hydroxytylophorine

Zhang

et al. 2017

Sci Rep

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“…Gratifyingly, treatment of 10 with H 2 in the presence of Pd on carbon cleanly transformed the enol ether into the saturated fused oxazeninones 11 (Scheme ). Cyclizations of this type are rare, but are have been used before on related structures to synthesize the natural product cleavamine, which also contains a bridged nine‐membered azaheterocycle core structure …”

Section: Resultsmentioning

confidence: 99%

“…Cyclizations of this type are rare, but are have been used before on related structures to synthesize the natural product cleavamine, which also contains a bridged nine-membered azaheterocycle core structure. [17]…”

Section: Resultsmentioning

confidence: 99%

Regio‐ and Diastereoselective Functionalization of 3‐Amino‐hexahydrooxazoninones

et al. 2018

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The regio‐ and diastereoselectivity of transformations of nine‐membered lactams with a Z double bond in the cyclic tether towards building blocks for medicinal chemistry was evaluated. To this end, 3‐aminohexahydrooxazoninones were synthesized using a standard ring‐closing metathesis (RCM) approach of easily available O,N‐bisallylated serine derivatives. The obtained Z double bond in the medium sized lactam was used as a handle to evaluate the stereoselectivity of electrophile induced transformations. It was shown that dibromination and electrophilic activation by NBS followed by attack of O‐nucleophiles proceeded in a diastereoselective manner. Cyclization of obtained bromohydrins and face‐selective epoxidation gave access to both diastereomers of the epoxidized lactams. Finally, a Heck‐reaction of a bromobenzyl moiety at the lactam N‐atom with the Z‐double bond resulted in the diastereoselective formation of bicyclic bridged nine‐membered lactams.

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“…RCM was also found to be a useful tool to construct the nine-membered ring system present in indole containing natural products (e. g., (AE)-cleavamine, Figure 5). [19] In general, there are large number of natural and unnatural compounds that contains indole ring, which are challenging synthetic targets. [20] In this context, synthesis of cyclophane derivatives containing both pyridine and indole systems has been described.…”

Section: Synthesis Of Cyclophanes Via a Rcm Protocolmentioning

confidence: 99%

Design and Synthesis of Polycycles, Heterocycles, and Macrocycles via Strategic Utilization of Ring‐Closing Metathesis

Kotha

Meshram

Dommaraju

2018

The Chemical Record

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In this perspective, we summarize new synthetic approaches for the construction of various polycyclic compounds involving ring-closing metathesis as a key step. In this regard, we used ring-closing metathesis in combination with other popular reactions like Suzuki-Miyaura coupling, Claisen rearrangement, Fischer indolization, Grignard addition, Diels-Alder reaction, and [2+2] cycloaddition reaction etc. To this end, a variety of functional molecules such as α-amino acids, cyclophanes, heterocycles, propellanes, spirocycles, and macrocycles have been prepared. The strategies developed and the molecules prepared here play a key role in designing new materials and also act as lead compounds in drug design. The strategies and tactics developed here are useful to design polycycles, macrocycles, and heterocycles of diverse ring systems.

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A Straightforward Synthetic Entry to Cleavamine-Type Indole Alkaloids by a Ring-Closing Metathesis−Vinyl Halide Heck Cyclization Strategy

Cited by 31 publications

References 33 publications

Total synthesis of the reported structure of 13a-hydroxytylophorine

Total synthesis of the reported structure of 13a-hydroxytylophorine

Regio‐ and Diastereoselective Functionalization of 3‐Amino‐hexahydrooxazoninones

Design and Synthesis of Polycycles, Heterocycles, and Macrocycles via Strategic Utilization of Ring‐Closing Metathesis

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