Synthesis of cyclopropanes by the reaction of olefins with dialkylzinc and methylene iodide

Furukawa, Junji; Kawabata, Nariyoshi; Nishimura, Jun

doi:10.1016/0040-4020(68)89007-6

Cited by 408 publications

(206 citation statements)

References 24 publications

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“…FAMEs were recovered from the scraped silica bands by elution with hexane͞diethyl ether (2:1, vol͞vol), and analyzed by GC͞MS. A racemic methyl cis-dihydrosterculate standard was prepared by reaction of methyl oleate with diiodomethane and diethylzinc in hexane (25).…”

Section: Methodsmentioning

confidence: 99%

Carbocyclic fatty acids in plants: Biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida

Bao

Katz

Pollard

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

132

100

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Fatty acids containing three-member carbocyclic rings are found in bacteria and plants. Bacteria synthesize cyclopropane fatty acids (CPA-FAs) only by the addition of a methylene group from Sadenosylmethionine to the cis-double bond of monoenoic phospholipid-bound fatty acids. In plants CPA-FAs are usually minor components with cyclopropene fatty acids (CPE-FAs) more abundant. Sterculia foetida seed oil contains 65-78% CPE-FAs, principally sterculic acid. To address carbocyclic fatty acid synthesis in plants, a cDNA library was constructed from developing seeds during the period of maximum oil deposition. About 0.4% of 5,300 expressed sequence tags were derived from one gene, which shared similarities to the bacterial CPA-FA synthase. However, the predicted protein is twice as large as the bacterial homolog and represents a fusion of an FAD-containing oxidase at the N terminus and a methyltransferase at the C terminus. Functional analysis of the isolated full-length cDNA was conducted in tobacco suspension cells where its expression resulted in the accumulation of up to 6.2% dihydrosterculate of total fatty acids. In addition, the dihydrosterculate was specifically labeled by [methyl-14 C]methionine and by [ 14 C]oleic acid in the transgenic tobacco cells. In in vitro assay of S. foetida seed extracts, S-adenosylmethionine served as a methylene donor for the synthesis of dihydrosterculate from oleate. Dihydrosterculate accumulated largely in phosphatidylcholine in both systems. Together, a CPA-FA synthase was identified from S. foetida, and the pathway in higher plants that produce carbocyclic fatty acids was defined as by transfer of C 1 units, most likely from S-adenosylmethionine to oleate.

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Section: Methodsmentioning

confidence: 99%

Carbocyclic fatty acids in plants: Biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida

Bao

Katz

Pollard

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

132

100

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“…A similar outcome was observed in the thermal chemistry of spiro[bicyclo[3.2.0]hept-2-ene-6,1'-cyclopropane] (12) in that only one of two potential CPC rearrangement products was observed [21]. The justification for this phenomenon was based on the assumption of a short lifetime for the resultant homoallylic radical that would preclude the exploration of all possible conformational space.…”

Section: Scheme 9 Structures Of Compounds 11 and 12mentioning

confidence: 69%

“…Wittig methylenation afforded 5-vinylbicyclo[2.2.2]oct-2-ene (5), whose 13 C-NMR spectrum revealed four downfield and six upfield signals. In contrast to our failed attempt to secure 5-cyclopropylnorbornene by selective kinetic cyclopropanation of vinylnorbornene [11] using the Furukawa modification of the Simmons-Smith reaction [12], identical conditions resulted in excellent conversion of 5 to 5-cyclopropylbicyclo-[2.2.2]oct-2-ene (2). Our explanation for this high degree of regioselectivity is that the syn-hydrogens on the saturated -CH 2 CH 2 -bridge obstruct the exo face of the endocyclic olefin from reacting with the carbenoid complex.…”

Section: Syntheses and Spectral Characterizationsmentioning

confidence: 81%

Gas Phase Thermal Reactions of exo-8-Cyclopropyl-bicyclo[4.2.0]oct-2-ene (1-exo)

et al. 2014

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Abstract:The title compound 1-exo (with minor amounts of its C8 epimer 1-endo) was prepared by Wolff-Kishner reduction of the cycloadduct of 1,3-cyclohexadiene and cyclopropylketene. The [1,3]-migration product 2-endo was synthesized by efficient selective cyclopropanation of endo-5-vinylbicyclo[2.2.2]oct-2-ene at the exocyclic π-bond. Gas phase thermal reactions of 1-exo afforded C8 epimerization to 1-endo, [1,3]-migrations to 2-exo and 2-endo, direct fragmentation to cyclohexadiene and vinylcyclopropane, and CPC rearrangement in the following relative kinetic order: k ep > k 13 > k f > k CPC .

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“…The required ring expansion of 24 was conveniently performed via the method reported by Saegusa et al (30). Thus, cyclopropanation (31) of the en01 silyl ether 25, derived (32) from the ketone 24, produced a mixture of the cyclopropanes 26 and 27, in a ratio of approximately 2 :…”

Section: Resultsmentioning

confidence: 99%

Annulations leading to diene systems. Total syntheses of the dolastane-type diterpenoids (±)-(5S,12R,14S)-dolasta-1(15),7,9-trien-14-ol and (±)-amijitrienol

Piers¹,

Friesen²

1992

Can. J. Chem.

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Annulations leading to diene systems. Total syntheses of the dolastane-type diterpenoids (~)-(5S,12R,14S)-dolasta-1(15),7,9-trien-14-01 and (2)-amijitrienol Chem. 70, 1204Chem. 70, (1992. Alkylation of the substituted cycloalkanones 14ci-el and 30 with (Z)-l-bromo-4-methyl-3-trimethylstannyl-2-pentene (13) produced compounds 150-d and 33, which were readily converted into the corresponding en01 trifluoromethanesulfonates (triflates) 160-el and 34. Intramolecular Pd(0)-catalyzed coupling of the vinylstannane and en01 triflate functions in 160-d and 34 provided the dienes 170-d and 35. The annulation product 35 served as a suitable starting material for the total syntheses of the dolastane diterpenoids (5)-(5S, 12R, 14s)-dolasta-1(15),7,9-trien-14-01 (2) and (?)-amijitrienol (3). The key steps of the synthesis of (5) [Traduit par la rCdaction]

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Synthesis of cyclopropanes by the reaction of olefins with dialkylzinc and methylene iodide

Cited by 408 publications

References 24 publications

Carbocyclic fatty acids in plants: Biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida

Carbocyclic fatty acids in plants: Biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida

Gas Phase Thermal Reactions of exo-8-Cyclopropyl-bicyclo[4.2.0]oct-2-ene (1-exo)

Annulations leading to diene systems. Total syntheses of the dolastane-type diterpenoids (±)-(5S,12R,14S)-dolasta-1(15),7,9-trien-14-ol and (±)-amijitrienol

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