Synthesis of cis,cis,cis-1-alkylidene-2,3,4,5-tetrakis(diphenylphosphinomethyl)cyclopentanes

Reynaud, Céline; Fall, Yacoub; Feuerstein, Marie; Doucet, Henri; Santelli, Maurice

doi:10.1016/j.tet.2009.07.016

Cited by 11 publications

(9 citation statements)

References 44 publications

(30 reference statements)

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“…Total yield of both isomers is 86 % (230 g). 1 H and 13 C NMR of 3a/b were in agreement with the published data (synthesis at the 100 mmol scale) . TLC (hexane/diethyl ether, 3:1): for 3a R f = 0.4, for 3b R f = 0.3.…”

Section: Methodssupporting

confidence: 89%

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Preparation of a Key Tetraene Precursor for the Synthesis of Long Acenes

et al. 2020

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The tetraene 7,7‐dimethoxy‐2,3,5,6‐tetramethylenebicyclo[2.2.1]heptane is a key compound for the preparation of a large variety of acenes protected by a carbonyl bridge. We report herein a medium scale preparation in seven steps of this valuable starting material. Diels–Alder addition between 6,6‐dimethtyl fulvene and maleic anhydride, followed by carboxylation, ozonolysis of the double bond, reduction of the four ester groups, then chlorination of the alcohol groups and dehydrochlorination give the target compound in 17 % overall yield.

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Section: Methodssupporting

confidence: 89%

“…Diels‐Alder addition between 6,6‐dimethylfulvene 2 and maleic anhydride gives a ca 1:1 mixture of endo ‐ and exo ‐isomers 3a and 3b in around 90 % yield . The next step is a palladium catalysed carboxylation according to Stille .…”

Section: Resultsmentioning

confidence: 99%

Preparation of a Key Tetraene Precursor for the Synthesis of Long Acenes

et al. 2020

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“…Rac-B 8 ( Figure 8) has been copolymerized with cyclooctene by ruthenium initiators to give a copolymer that contains a mixture of cis and trans double bonds. 2 The copolymer prepared using Grubbs 1 st generation initiator (82% yield, 73% A 1 -alt-B 8 ) could be improved to ~90% A 1 -alt-B 8 employing a modified Grubbs 2 nd generation initiator. The polymerization of 100 equivalents of A 1 and B 8 (0.1 M in CDCl 3 ) by 1 was complete within 2 h at 22 °C to yield a CDCl 3 -soluble, yellow polymer.…”

Section: H a H B H A H B H A H B H A H B H A H B H A H B H A H Bmentioning

confidence: 99%

“…In the last fifteen years ring-opening metathesis polymerization (ROMP) has been employed to make alternating AB copolymers. 2 The ideal circumstance for preparing an AB copolymer is one in which two monomers that are only slowly homopolymerized undergo cross polymerization. An example is the copolymerization of 1-substituted cyclobutenes and cyclohexene with ruthenium alkylidene initiators; 2a 1-substituted cyclobutenes are not readily homopolymerized for steric reasons and the free energy for polymerization of cyclohexene is positive, so only one cyclohexene (it is proposed) is incorporated between two units of cyclobutene.…”

Section: Introductionmentioning

confidence: 99%

“…We recently reported the synthesis of four alternating trans-A-alt-B copolymers from one of two large norbornadienes (B 1 or B 2 , Figure 1) and either cyclooctene (A 1 ) or cycloheptene (A 2 ) where Mo(NR)(CHCMe 2 Ph)[OCMe(CF 3 ) 2 ] 2 (R = 2,6-Me 2 C 6 H 3 (1) or 2,6-i-Pr 2 C 6 H 3 (2)) is the initiator. 5 Between 92% and 97% AB dyads are formed in the trans-A-alt-B copolymer from a 1:1 mixture of A and B, depending on the specific reaction and conditions employed.…”

Section: Introductionmentioning

confidence: 99%

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Formation of Alternating trans-A-alt-B Copolymers through Ring-Opening Metathesis Polymerization Initiated by Molybdenum Imido Alkylidene Complexes

2015

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Ring-opening metathesis polymerization (ROMP) is used to prepare trans-poly(A-alt-B) polymers from a 1:1 mixture of A and B where A is a cyclic olefin such as cyclooctene (A 1) or cycloheptene (A 2) and B is a large norbornadiene or norbornene derivative such as 2,3dicarbomethoxy-7-isopropylidenenorbornadiene (B 1) or dimethylspirobicyclo[2.2.1]hepta-2,5diene-2,3-dicarboxylate-7,1'-cyclopropane (B 2). The most successful initiators that were examined are of the type Mo(NR)(CHCMe 2 Ph)[OCMe(CF 3) 2 ] 2 (R = 2,6-Me 2 C 6 H 3 (1) or 2,6-i-Pr 2 C 6 H 3 (2)). The trans configuration of the AB linkages is proposed to result from the steric demand of B. Both anti-MB and syn-MB alkylidenes are observed during the copolymerization, where B was last inserted into a Mo=C bond, although anti-MB dominates as the reaction proceeds. Anti-MB is lower in energy than syn-MB, does not react readily with either A or B, and interconverts slowly with syn-MB through rotation about the Mo=C bond. Syn-MB does not readily react with B, but it does react slowly with A (rate constant ~1 M-1 s-1) to give anti-MA and one trans-AB linkage. Anti-MA then reacts with B (rate constant ~300 M-1 s-1 or larger) to give syn-MB and the second trans-AB linkage. The reaction has been modeled using experimental data in order to obtain the estimated rate constants above. The reaction between anti-MA and A is proposed to give rise to AA linkages, but AA dyads can amount to <5%. Several other possible A and B monomers, initiators, and conditions were explored.

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