A practical synthesis of 3(S)-methyl-heptanoic acid from (S)-citronellol

Breitenbach, Ralph; Chiu, Charles K.-F.; Massett, Stephen S.; Meltz, Morgan; Murtiashaw, C. W.; Pezzullo, Susan L.; Staigers, Thomas

doi:10.1016/0957-4166(96)00026-2

Cited by 18 publications

(9 citation statements)

References 25 publications

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“…Labeling Experiments. Since the above considerations call for isotopic labeling, both ( E )- and ( Z )-isomers of d 3 -labeled citronellal (±)- 1b and (±)- 1c were synthesized in a stereospecific manner, starting from the protected aldehyde 37 , readily obtained from the benzyl ether of citronellol via ozonization (Scheme ) . Wittig olefination of the latter aldehyde with Ph 3 PC(Me)CO 2 Et (CH 2 Cl 2 , 40 °C, 4 h) proceeded in a remarkably stereoselective manner, affording the conjugated ester 38 (93%) 40 as a 98:2 E / Z mixture.…”

Section: Resultsmentioning

confidence: 99%

“…Reduction of the latter ester with LiAlD 4 afforded d 2 -labeled alcohol 39 41 (89%; ≥98% of d 2 ), which on chlorination with N -chlorosuccinimide and Me 2 S (CH 2 Cl 2 , 0 °C, 5 h) afforded allylic chloride 40 (92%). Reduction of 40 with LiAlD 4 (Et 2 O, reflux for 6 h) gave the d 3 -derivative 41 (97%; ≥98% of d 2 ), whose debenzylation with Li in liquid ammonia ( 41 → 42 ; 91%), , followed by Swern oxidation provided ( E )-citronellal- d 3 ( 1b ) (98%; ≥97% of d 3 ).…”

Section: Resultsmentioning

confidence: 99%

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New Lewis-Acidic Molybdenum(II) and Tungsten(II) Catalysts for Intramolecular Carbonyl Ene and Prins Reactions. Reversal of the Stereoselectivity of Cyclization of Citronellal

et al. 1999

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New Mo(II) complexes BnEt(3)N(+)[Mo(CO)(4)ClBr(2)](-) (A) and Mo(CO)(5)(OTf)(2) (B) and their W(II) congeners D and E have been developed as catalysts for the title reactions. Unlike other Lewis acids, the latter catalysts exhibit cis-stereoselectivity in the cyclization of citronellal (1 --> 3 with A and 1 --> 5 with B). Isotopic labeling allowed formulation of the reaction mechanism, according to which these complexes act as bulky Lewis acids, eta(1)-coordinated to the carbonyl oxygen. The stereochemistry appears to be controlled by the protruding ligand L(p), which dictates the boatlike transition state III. The kinetically formed cis-alkenol 3 can be equilibrated by [Mo(CO)(4)Br(2)](2) (C) or ZnCl(2) to its trans-epimer 2 via a retro-ene reaction.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

New Lewis-Acidic Molybdenum(II) and Tungsten(II) Catalysts for Intramolecular Carbonyl Ene and Prins Reactions. Reversal of the Stereoselectivity of Cyclization of Citronellal

et al. 1999

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“…274 A practical route for the conversion of (S)-citronellol ent-37 into (3S)-methylheptanoic acid 54 has been described. 275 The gas-phase oxidation of linalool 22 has been investigated with a view to determining its possible contribution to the formation of atmospheric ozone and of photooxidation products such as formaldehyde. 276 The acylation of linalool 22 by acetic anhydride in a reaction which is catalysed by polymeric pyrrolidinopyridines has been described.…”

Section: 6-dimethyloctanesmentioning

confidence: 99%

Monoterpenoids

Grayson¹

1998

Nat. Prod. Rep.

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Species Principal constituents ReferenceAbies balsamea Mill -and -pinene, -phellandrene, limonene Achillea biebersteinii Afan piperitone, or cineol and camphor Aloysia triphylla (L'Herit.) Britton citral, limonene Alpinia conchigera Griff. cineol Alseuosmia macrophylla A. Cunn. flowers: linalool Ambrosia microcephala DC. camphor, bornyl acetate Amomum subulatum Roxb. cineol, -terpineol, -and -pinene Artemisia afra yomogi alcohol, artemisyl acetate Artemisia afra Willd. cineol, terpinen-4-ol, borneol Artemisia ordosica -and -pinene, sabinene Austromyrtus dulcis (C. T. White) L. S. Smith (chemotype) -pinene, cineol Boronia megastigma Nees. -ionone, 8-hydroxylinalyl esters, geranyloxy cinnamate Bouea macrophylla Griff. ( E)--ocimene, -pinene Calamintha cretica piperitenone, piperitenone oxide Calamintha incana (Sm.) Boiss. piperitenone oxide Callistemon speciosus Anthor. cineol, -pinene, -terpineol Canella winteriana Gaertn. stem and bark: cineol, terpinen-4-ol, -terpinyl acetate, -terpineol; leaves: myrcene Cedronella canariensis Webb et Berth. ssp. canariensis pinocarvone Chamelaucium uncinatum genotypes -pinene, citronellal, limonene, linalool, -terpinyl acetate Chenopodium ambrosioides limonene, trans-pinocarveol Chenopodium botrys -8 Chrysanthemum balsamata carvone, camphor Chrysanthemum lavandulaefolium menthol Cinnamomum camphora Nees et Ebermaier camphor, cineol, terpinen-4-ol, limonene Cinnamomum puciflorum -2 Citrus grandis limonene Clausena anisata (Willd.) J. D. Hook limonene, myrcene Coleus aromaticus carvacrol, camphor Coreopsis barteri Oliv. & Hiern limonene, -phellandrene Coreopsis grandis Hogg ex Sweet myrcene Coriandrum sativum seeds: linalool Coridothymus capitatus Reich. f. carvacrol 98, 99 Cunila fasiculata menthofuran Cunila microcephala menthofuran, limonene Curcuma aeruginosa Roxb. cineol, camphor Curcuma amada Roxb. myrcene Curcuma aromatica Salisb. cineol, camphor, isoborneol, camphene Curcuma cochinchinensis Gagnep. cineol Curcuma domestica -phellandrene, cineol, p-cymene, -pinene Curcuma pierreana Gagnep. Rhizome, stem: isoborneol, isobornyl acetate leaf: isoborneol, camphor Croton aubrevillei J. Leonard linalool Croton zambesicus Muell. Arg. linalool Cyclotrichum origanifolium (Labill.) Manden. et Scheng. cis-isopulegone, pulegone, isomenthone, menthol Cymbopogon caesius (Nees et Hook. et Arn.) Stapf. perillyl alcohol, geraniol, limonene Cymbopogon citratus (DC.) Stapf. citral, geraniol, myrcene, -and -pinene Cymbopogon khasianus (Munro ex Hack.) Bor. geraniol, geranyl acetate, linalool Cymbopogon schoenanthus piperitone, limonene Daphne mezereum flowers: linalool, linalyl oxides Echinophora chryantha Freyn et Sint. -phellandrene Egletes viscosa various terpenol acetates Elsholtzia ciliata (Thunb.) Hyland chemotype (a): elsholtzia ketone, -thujone chemotype (b): neral, geranial, limonene

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“…The synthesis of the C1–C12 fragment I began with known aldehyde 4 2 derived from ( S )-citronellal (Scheme 1). Aldehyde 4 and phenyltetrazolylsulfonyl ester 5 were joined in a Julia-Kociensky reaction3 (KHMDS, THF, −78 °C to −45 °C, 69%) to provide alkene 6 with excellent E selectivity.…”

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A Versatile Route to the Tulearin Class of Macrolactones: Synthesis of a Stereoisomer of Tulearin A

et al. 2009

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A versatile synthetic approach to the tulearin class of macrolactones has been developed and deployed to make a stereoisomer of tulearin A. The knowledge gained about structure and synthesis will expedite the assignment of the stereostructure of this new anti-cancer agent.In 2008, Kashman et al. reported the isolation of tulearin A (1) (Figure 1) from the marine sponge Madagascar Fascaplysinopsis sp. collected in the Salary Bay north of Tulear. 1 The structure of 1 was elucidated through interpretation of MS, IR, and various one-dimensional and two-dimensional NMR experiments. However, the relative and absolute stereochemistry of 1 remain unknown. Tulearin A (1) exhibits potent anti-proliferative activity against human leukemic cell lines K562 and UT7. Activity against K562 cells was notably better; a 0.5 µg/ mL solution of 1 inhibited ~60% of proliferation vs. 35% inhibition against the UT7 cells. 1Due to its promising biological activity and lack of a three-dimensional structure, we designed a synthetic strategy that was capable of producing any stereoisomer of tulearin A (1). These stereoisomers could be used to help assign the stereochemistry and to provide information about the stereostructure/activity relationship. Here we describe the single stereoisomer of tulearin 2.Our retrosynthetic plan (Figure 2) was to construct the complete structure through the union of three fragments: stannane 25 (the C20-C26 fragment), an acid of type I (the C1-C12 fragment), and vinyl iodide 20 (the C13-C19 fragment) through an esterification, ring-closing metathesis, and Stille coupling. Both acid I and iodide 20 originate from readily available (S)-citronellal (3), which already contains the methyl stereochemistry at C5 and C15. The stereocenters at C2 and C3 come from an asymmetric aldol reaction, while the substituents at C8 and C9 are installed through a Sharpless asymmetric dihydroxylation.The alcohol at C17 is formed through a Noyori reduction. The carbamate is challenging because the alcohols at C8 and C9 have to be orthogonally protected to allow its installation before the final deprotection. We envisioned that all of the fragments could be adjusted by choice of reagents to give any stereoisomer.The synthesis of the C1-C12 fragment I began with known aldehyde 4 2 derived from (S)-citronellal (Scheme 1). Aldehyde 4 and phenyltetrazolylsulfonyl ester 5 were joined in a JuliaKociensky reaction 3 (KHMDS, THF, −78 °C to −45 °C, 69%) to provide alkene 6 with excellent E selectivity. Sharpless asymmetric dihydroxylation 4 of 6 with AD-mix-α in the presence of methanesulfonamide (t-BuOH/H 2 O 1:1, 0 °C, 96 h) gave rise to a diol that spontaneously cyclized to form the 5-membered lactone 7 exclusively in 85% yield. Thus, the hydroxy groups at C8-C9 (tulearin A numbering) were differentiated, and C8 group was protected as a p-methoxybenzyl ether [PMBOC(=NH)CCl 3 , La(OTf) 3 , toluene, 12 h, 85%] to give lactone 8. The p-methoxybenzyl (PMB) group was chosen because it can later be removed in the presence of silyl prote...

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A practical synthesis of 3(S)-methyl-heptanoic acid from (S)-citronellol

Cited by 18 publications

References 25 publications

New Lewis-Acidic Molybdenum(II) and Tungsten(II) Catalysts for Intramolecular Carbonyl Ene and Prins Reactions. Reversal of the Stereoselectivity of Cyclization of Citronellal

New Lewis-Acidic Molybdenum(II) and Tungsten(II) Catalysts for Intramolecular Carbonyl Ene and Prins Reactions. Reversal of the Stereoselectivity of Cyclization of Citronellal

Monoterpenoids

A Versatile Route to the Tulearin Class of Macrolactones: Synthesis of a Stereoisomer of Tulearin A

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