The use of the RambergBäcklund rearrangement for the formation of aza-macrocycles: a total synthesis of manzamine C

MaGee, David I.; Beck, Ellen J.

doi:10.1139/v00-103

Cited by 13 publications

(26 citation statements)

References 24 publications

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“…20 Although all attempts to initiate this reaction failed, the sulfone precursors turned out to undergo the desired ring contraction when submitted to a flash vacuum pyrolysis under carefully adjusted conditions. Scheme 1 shows the synthesis of sulfone 14, the precursor leading up to combretastatin D-2 4.…”

Section: Resultsmentioning

confidence: 99%

Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis

Harras¹,

Milius²,

Aitken

et al. 2016

J. Org. Chem.

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RECEIVEDWe report the syntheses of combretastatins D-2 and D-4, as well as a formal synthesis of combretastatin D-1 by a conceptually new route harnessing a ring-contracting flash vacuum pyrolytic extrusion of sulfur dioxide from the respective 16-membered sulfone precursors. Via flash vacuum pyrolysis even metaparacyclophanes as small and strained as the hitherto unknown oxa[1.5]metaparacyclophane could be prepared as a side product en route to combretastatin D-2 by synchronous extrusion of SO 2 and CO 2 .

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Section: Resultsmentioning

confidence: 99%

Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis

Harras¹,

Milius²,

Aitken

et al. 2016

J. Org. Chem.

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“…Dialdehyde 101 reacted to give a chromatographically separable mixture of ( Z )‐ 102 (37 %) and ( E )‐ 102 (25 %) (Scheme ) 72. Viewing this reaction from the same perspective as the previous two sections would lead to the classification of 102 as an orthocyclophane, but the meta ‐substituted benzene ring in the tether of 101 renders the product a derivative of 10metacyclophane. A very surprising result was the McMurry reaction of dialdehyde 28 , which produced ( Z,E,Z,Z )‐[6.2](2,5)furanophane‐1,3,5,11‐triene ( 103 ) in 7 % yield (Scheme ) 29.…”

Section: The Mcmurry and Related Reactionsmentioning

confidence: 97%

“…In this case, RCM of 225 led to the formation of a 1:1 mixture of two atropisomeric 10paracyclophanes 226 and 227 in 69 % combined yield (Scheme ). The lack of selectivity notwithstanding, the formation of a 10paracyclophane system in good yield using RCM is a significant accomplishment.…”

Section: Ring‐closing Metathesismentioning

confidence: 99%

“…Even though it applies to pre‐existing cyclophanes, it warrants attention in the context of this review because both bonds of the newly formed alkene are generated during the reaction. Within the broader scope of organic synthesis, the Ramberg–Bäcklund reaction has been exploited frequently to introduce a double bond into large rings,10 small rings11 and more exotic ring systems such as cyclic enediynes 12. However, it has not performed well in the synthesis of cyclophanes.…”

Section: The Ramberg–bäcklund Reactionmentioning

confidence: 99%

“…RCM reactions of substituted metallocenes can also be included in Category A if the metal atom is viewed as a linker between two aromatic systems. In this regard, 4zirconocenophane ( Z )‐ 197 (50 %) and 10zirconocenophane ( E )‐ 198 (25 %) were synthesized from the respective dienes 196 a and 196 b (Scheme ) 120. Clearly, the longer bridge is able to accommodate an E ‐configured alkene.…”

Section: Ring‐closing Metathesismentioning

confidence: 99%

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Olefination Reactions in the Synthesis of Cyclophanes

Bodwell

Nandaluru

2012

Israel Journal of Chemistry

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A survey of olefination reactions that have been used in the synthesis of cyclophanes is presented. This covers the Ramberg-Bäcklund reaction, the Wittig and related reactions, the McMurry and related reactions, ring-closing metathesis (alkenes, alkynes and ene-ynes), aldol condensations and Siegrist reactions, as well as miscellaneous reactions. The McMurry reaction and ring-closing metathesis have enjoyed the greatest popularity in recent years, but they are typically used for complementary purposes. In virtually all cases, the McMurry reaction is used to install a twocarbon (1,2-ethenylene) bridge, whereas ring-closing metathesis is used to construct bridges that are at least fourmembered, but usually considerably longer. Some wellknown olefinations have seen little or no use in the field of cyclophane chemistry.The Ramberg-Bäcklund reaction [9] is the final step in a two-to three-step thioether-to-alkene conversion. As such, it appears to be well-suited for the synthesis of alkene-containing cyclophanes. Even though it applies to pre-existing cyclophanes, it warrants attention in the context of this review because both bonds of the newly formed alkene are generated during the reaction. Within the broader scope of organic synthesis, the Ramberg-Bäcklund reaction has been exploited frequently to introduce a double bond into large rings, [10] small rings [11] and more exotic ring systems such as cyclic enediynes. [12] However, it has not performed well in the synthesis of cyclophanes.The first cyclophanes to be synthesized using the Ramberg-Bäcklund reaction were the isomeric biphenylophanes (Z,Z)-7 and (E,E)-7 (Scheme 3). [13] As expected from mechanistic considerations, [14] they were formed stereospecifically in good yield (both 65 %) from the diastereomeric sulfones meso-6 and (AE)-6, respectively. Interestingly, the report of these very good results came shortly after Boekelheide wrote that "the Ramberg-Bäcklund reaction is unsatisfactory when applied to 2,11-dithia-[3.3]cyclophanes". [15] Prior to Boekelheides comment on the Ramberg-Bäcklund reaction, Martel reported that a Ramberg-Prof. Graham Bodwell obtained his B.Sc. and M.Sc. from the University of Victoria, Canada, working with Prof. Reginald Mitchell on cyclophanes. He then moved to Braunschweig, Germany, where he joined the group of Prof. Dr. Henning Hopf as a "Doktorand". Cyclophanes were also the focus of his doctoral research. He then took a break from cyclophanes and worked in the field of asymmetric synthesis as a post-doctoral fellow with Prof. Steve Davies at Oxford University. He then accepted a faculty position at Memorial University, where he now holds the rank of Professor. Cyclophanes have always been one of his core research interests.Penchal Reddy Nandaluru obtained his B.Sc. and M.Sc. from Sri Venkateswara University, India, and then worked as a chemist with AVRA Laboratories in India before joining the group of Prof. Graham Bodwell at Memorial University in St. John's, NL, Canada. The main theme of his doctoral research is the appli...

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ChemInform Abstract: The Use of the Ramberg—Baecklund Rearrangement for the Formation of Aza‐Macrocycles: A Total Synthesis of Manzamine C.

MaGee

Beck

2000

ChemInform

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The Use of the Ramberg-Baecklund Rearrangement for the Formation of Aza-Macrocycles: A Total Synthesis of Manzamine C. -Key step of the novel synthesis of manzamine C (VI) is the highly stereoselective Ramberg-Baecklund rearrangement of a macrocyclic α-chlorosulfone (I) in the presence of potassium tert-butylate, which provides access to the E-azacycloundecene (II). Since no conditions for the direct rearrangement to Z-azacycloundecene (V) are found, E-alkene (II) is isomerized via an dihydroxylation-cis-epoxidation-deoxygenation sequence.-(MAGEE, DAVID I.; BECK, ELLEN J.; Can. J. Chem. 78 (2000Chem. 78 ( ) 8, 1060Chem. 78 ( -1066 Dep. Chem., Univ. New Brunswick, Fredericton, New Brunswick E3B 6E2, Can.; EN)

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The use of the RambergBäcklund rearrangement for the formation of aza-macrocycles: a total synthesis of manzamine C

Abstract: A total synthesis of the marine alkaloid manzamine C has been accomplished. A Ramberg-Bäcklund reaction was used as a key step to construct the required azacycloundecene ring.Key words: alkaloid, macrocycle, RambergBäcklund, manzamine C.

Cited by 13 publications

References 24 publications

Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis

Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis

Olefination Reactions in the Synthesis of Cyclophanes

ChemInform Abstract: The Use of the Ramberg—Baecklund Rearrangement for the Formation of Aza‐Macrocycles: A Total Synthesis of Manzamine C.

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The use of the RambergBäcklund rearrangement for the formation of aza-macrocycles: a total synthesis of manzamine C

Abstract: A total synthesis of the marine alkaloid manzamine C has been accomplished. A Ramberg-Bäcklund reaction was used as a key step to construct the required azacycloundecene ring.Key words: alkaloid, macrocycle, RambergBäcklund, manzamine C.

Cited by 13 publications

References 24 publications

Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis

Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis

Olefination Reactions in the Synthesis of Cyclophanes

ChemInform Abstract: The Use of the Ramberg—Baecklund Rearrangement for the Formation of Aza‐Macrocycles: A Total Synthesis of Manzamine C.

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The use of the RambergBäcklund rearrangement for the formation of aza-macrocycles: a total synthesis of manzamine C

Abstract: A total synthesis of the marine alkaloid manzamine C has been accomplished. A Ramberg-Bäcklund reaction was used as a key step to construct the required azacycloundecene ring.Key words: alkaloid, macrocycle, RambergBäcklund, manzamine C.