A Highly Efficient Synthesis of <i>Z</i>‐Macrocycles Using Stereoretentive, Ruthenium‐Based Metathesis Catalysts

Ahmed, Tonia S.; Grubbs, Robert H.

doi:10.1002/anie.201704670

Cited by 37 publications

(26 citation statements)

References 30 publications

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“…10 and 11, 12 and 13,e tc.) [58][59][60] It is possible that in this case the studied effect is less visible than for biggerr ings RCM. This way we wanted to test how different substitution patterns of the CÀCd ouble bond of the acid fragment (H or C 8 H 17 )i nfluence the RCM macrocyclization, while keepingt he alcohol fragment the same.…”

Section: Scope and Limitation Studymentioning

confidence: 90%

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Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

et al. 2018

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Macrocyclic musk belongs to a well-known and valued class of the fragrance family. Originally, natural musks were obtained from rectal musk glands which often led to the death of the animals. Recently, a lot of effort was invested to obtain such macrocycles in a synthetic way. This research presents a study on the preparation of macrocyclic lactones with the musk scent by ring-closing metathesis (RCM) using biomass-derived starting materials: oleic and 9-decenoic acid. An experimental rule correlating the C-C double bond substitution pattern in the starting diene and the yield for the RCM macrocyclization was proposed.

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Section: Scope and Limitation Studymentioning

confidence: 90%

“…To our knowledge,there are only af ew examples of RCM reactions leadingt o1 5-membered rings. [58][59][60] It is possible that in this case the studied effect is less visible than for biggerr ings RCM.…”

Section: Scope and Limitation Studymentioning

confidence: 90%

Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

et al. 2018

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“…Small rings will favor the Z ‐isomer in order to minimize steric repulsion, whereas for macrocycles, the resultant ratio of E ‐ and Z ‐olefins typically reflects the thermodynamic energy difference between the two isomers, which is approximately 9:1, E : Z , but can vary depending on the particular reaction . It should be noted that while strategies have been elucidated to dictate the geometry of macrocycles synthesized through RCM, during the polymerization step as the double bond reacts and undergoes the cycloreversion of the metallocyclobutane, the initial geometry is lost . If it is of interest to dictate the stereochemistry at this stage, strategies can be employed such as prolonged reaction times to drive the thermodynamically favored E‐ isomer to high yields, or Z‐ isomers can be obtained through the use of catalysts which dictate the approach of the monomer to the catalyst‐bound alkylidene …”

Section: Macrocycle Synthesismentioning

confidence: 99%

Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Pearce

Foster

O’Reilly

2019

J. Polym. Sci. Part A: Polym. Chem.

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Entropy‐driven ROMP (ED‐ROMP) involves polymerization of olefin‐containing macrocyclic monomers under entropically favorable conditions. Macrocycles can be prepared from a variety of interesting molecules which, when polymerized, impart unique functionality to the resulting polymer backbone such as degradable linkages, biological moieties, crystallizable groups, or supramolecular hosts. In addition, the sequence of atoms in the cyclic monomer is preserved within the polymer repeating units, allowing for facile preparation of sequence‐defined polymers. In this review article, we consider how the mechanism of ROMP applies to ED polymerizations, how olefinic macrocycles are synthesized, and how polymerization conditions can be tuned to maximize conversion. Recent works in the past 10 years are highlighted, with emphasis on methods which can be employed to achieve fast polymerization kinetics and/or selective head‐to‐tail regiochemistry, thus improving polymerization control. ED‐ROMP, with its unique capability to produce polymers with well‐defined polymer backbone microstructure, represents an essential complement to other, well‐established, metathesis methodologies such as ROMP. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1621–1634

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“…Thefolded conformations of these a,w-dienes in 1b bring the ends closer together and expose them to reagents in the bulk solution. These characteristics promote medium to large ring cyclizationsi na mide-forming reactions, [2,14] and their application to ring-closing metathesis (RCM) reactions seemed possible.O lefin metathesis is widely used for ring formation, [15] but medium rings represent challenges, [16] as torsions and transannular strains arising during the reaction result in relatively inefficient cyclization.…”

Section: Angewandte Chemiementioning

confidence: 99%

Cavitands as Containers for α,ω‐Dienes and Chaperones for Olefin Metathesis

Petsalakis

Theodorakopoulos

et al. 2018

Angew Chem Int Ed

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Described herein is the behavior of a,w-dienes sequestered within cavitands in aqueous (D 2 O) solution. Hydrophobic forces drive the dienes into the cavitands in conformations that best fill the available space.Shorter dienes (C9 and C10) bind in compressed conformations that tumble rapidly in the cavitands.L onger dienes induce capsule formation between cavitands with self-complementary hydrogen bonding sites,w here the dienes exist in extended conformations.Incavitands unable to form capsules,longer dienes adopt folded structures.T he wider open ends allowt he synthesis of medium-sized cycloalkenes by ring-closing metathesis reactions with the Hoveyda-Grubbs-II catalyst. Yields of cycloheptene and cyclooctene were enhanced by the chaperones in water when compared with reactions of the free dienes in either aqueous media or chloroform, and even cyclononene could be prepared within the cavitand.Molecularcontainerhostshavereceivedmuchattentionfor their ability to confine guest molecules and affect their reactivity.T he use of self-assembly has expanded the use of these containers for the promotion of reactions in small spaces. [1] We recently reported the synthesis and characterization of the deep cavitand 1a [2] (Figure 1). Thes elfcomplementary pattern of hydrogen bond donors and acceptors on the upper rim was devised by de Mendoza, [3] who showed that dimerization to host capsules occurs with suitable guests in organic solvents.W ef ound that pyridinium or methylimidazolium "feet" provided good solubility in water, and the formation of capsules occurs even in aqueous solutions when large hydrophobic guests are present. [4] To prevent such dimerization, we exhaustively N-methylated the benzimidazolones of the upper rim to form the octamethyl urea 1b (Supporting Information). Thec avitand 1b showed good solubility in water (D 2 O), where it exists as avelcrand [5] dimer in the absence of guests.H erein we report the complexation of symmetrical aliphatic a,w-dienes (C9-C14) with cavitands 1a and 1b,a nd their applications for olefin metathesis in otherwise reluctant cyclizations.Alkenes bound inside synthetic host structures are not often reported [6] because the NMR signals of the olefinic protons are rarely observed given the overlap with the signals of the cavitands. [7] We used commercially available a,w-dienes:C 91 ,8-nonadiene (2a), C10 1,9-decadiene (2b), C11 1,10-undecadiene (2c), C12 1,11-dodecadiene (2d), and C14 1,13-tetradecadiene (2f). TheC13 1,12-tridecadiene (2e) was synthesized by reaction of 10-bromo-1-decene with allylmagnesium bromide. [8] Brief sonication of these a,w-dienes (0.5 mm)w ith 1a (0.5 mm)i nw ater (D 2 O) gave host-guest complexes with 1 HNMR signals of the guest characteristically upfield-shifted by the shielding of the aromatic panels of the host structure (Figure 2; Supporting Information). Thelonger a,w-dienes 2c, 2d, 2e,and 2fshow signals that are spread out between d = 1.5 and À2.0 ppm (Figure 2). Thes ignals for terminal vinyl hydrogen of C11 appears at d = 0.05 ppm (Dd = À...

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A Highly Efficient Synthesis of Z‐Macrocycles Using Stereoretentive, Ruthenium‐Based Metathesis Catalysts

Cited by 37 publications

References 30 publications

Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Cavitands as Containers for α,ω‐Dienes and Chaperones for Olefin Metathesis

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