Synthesis of .omega.-bromo ketones

House, Herbert O.; Chu, Chia-Yeh; Phillips, William V.; Sayer, Trevor S. B.; Yau, Cheuk-Chung

doi:10.1021/jo00430a009

Cited by 36 publications

(14 citation statements)

References 8 publications

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“…followed by tribr~mocarbo~ylic acid 5 (290% yield) by the the addition of excess acid (HcI. 2 N) gave crude photochemically induced addition of hydrogen diol lactone 8 which yielded tricyclic orthoester 1 bromide (hv, pentane, (8)). Treatment of tribromo-(88%) upon reflux in benzene.…”

Section: R = Hmentioning

confidence: 99%

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.0^1,6]tetradecane

Beaulieu¹,

Deslongchamps²

1980

Can. J. Chem.

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NORMAXD BEALJLIEU and PIERRE DESLONGCHAMPS. Can. J. Chem. 58.875 (1980). A simple and convenient synthesis of tricyclic orthoester 1 (2.10.1l-trioxatricycl0[4.4.4~O~~~]tetradecane) is described.NORMAND BEAULIEU et PIERRE DESLOKGCHAI\.IPS. Can. J. Chem. 58, 875 (1980). to report a new synthesis of tricyclic orthoester 1 in which there is improvement on the number of steps. reaction conditions. ease of product isola-(RO-CH2-CH2-CH2),C-COOCH, tion. and overall yield. R = HEthyl his-ally1 acetate 2, which can be conve-10 R = CH,CO niently prepared by alkylation of diethyl malonate (5) with ally1 bromide followed by decarboxylation (NaCl in DMSO-H,O, (6)), was used as starting material.Ethyl bis-ally1 acetate 2 was alkylated (LDA, CH,==CH--CH2-Br, HMPT. -78"C, (7)) to give ethyl tri-ally1 acetate 3 (290% yield). Basic hydrolysis of 3 (KOH, C2H,0H, reflux, 15 days),6 up P gave the corresponding carboxylic acid 4 (95% yield) which was converted into the known (4) CH30H3 room temperature, 30 min? followed by tribr~mocarbo~ylic acid 5 (290% yield) by the the addition of excess acid (HcI. 2 N) gave crude photochemically induced addition of hydrogen diol lactone 8 which yielded tricyclic orthoester 1 bromide (hv, pentane, (8)). Treatment of tribromo-(88%) upon reflux in benzene. The tricyclic orcarboxylic acid 5 with triethylamine in thoester 1 was also obtained (66%) by treatment of dichloromethane furnished the expected dj-diacetate lactone 7 under acidic conditions 2.4 N bromoIactone 4 (290% yield) which was further HCl-(1: 11, room temperature, 2 h) followed transformed (CH,COONa. HMPT, room temper-by the addition of benzene and distillation. ature. 2 h , (9)) into the diacetate lactone 7 (50% Diacetaee lactone ' 9 was also hydrolysed with yield).triethylamine in methanol (4 days, room temperaBasic hydrolysis of &acetate lactone 7 (K,CO,, ture, (10)) to yield crude triol methyl ester 9 which was characterized spectroscopicaliy and by its 'Holder of a Natural Sciences and Englneenng ~~~~~~~h conversion into triacetate methyl ester 18. Treat- For personal use only.

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Section: R = Hmentioning

confidence: 99%

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.0^1,6]tetradecane

Beaulieu¹,

Deslongchamps²

1980

Can. J. Chem.

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“…When 4,4‐dimethylcyclohexa‐2,5‐dienone ( 2a )2d was allowed to react with vinylmagnesium bromide (2 equiv.) in dry THF at –50 °C in the presence of copper bromide · dimethyl sulfide (10 mol %)6 for 30 min, vinylcyclohexenone 3a was successfully isolated in 83 % yield by rapid chromatographic work‐up. Following this same procedure, compound 3a was exclusively converted into the trans ‐divinyl derivative 4a in 77 % yield (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Regio‐ and Diastereoselective Conjugate Addition to 4,4‐Dimethylcyclohexadienones

2005

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Conjugate addition of vinyl cuprate and dimethyl malonate to 4,4‐dimethylcyclohexa‐2,5‐dienones has allowed facile access to mono‐ and bis‐adducts in satisfactory yields. While the high diastereoselectivity of such processes to afford trans‐bis‐adducts was predictable, an unprecedented regioselectivity was observed with 2,4,4‐trimethylcyclohexa‐2,5‐dienone, with the first addition occurring exclusively at the C‐5 carbon atom (distal from the methyl group) and with the second addition of a bulky nucleophile such as dimethyl malonate even prevented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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“…Oxidation of 6-methylenecyclodecanol (9) with chromic trioxide in pyridine [ 161 gave 6-methylenecyclodecanone (12). However, the light-induced radical-chain addition of HBr to 12 in pentane solution [17] did not yield any bromide llc. Also fruitless were several attempts to protect the keto function in 12 owing to the high tendency of 1,6-disubstituted cyclodecanes to undergo transannular cyclization.…”

Section: )mentioning

confidence: 91%

Synthesis and Dimerization of Bicyclo [4.4.1] undec‐1 (11)‐ene, a Bridged trans‐Cycloheptene

Becker¹,

Chappuis²

1979

Helvetica Chimica Acta

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The synthesis of bicyclo[4.4.l]undec-1(ll)-ene (5) by intr,amolecular Wittig reaction is described. The Bredt olefin could not be isolated, but dimerized rapidly to a novel compound 15 containing a cyclopropane ring. The olefin 5 was trapped in situ by 2,5-diphenylbenzo [clfuran.Introduction. -The question of the limits of Bredt's rule is of considerable current interest [l] [2]. It is now generally accepted that the strain of a bicyclic or polycyclic bridgehead olefin (Bredt olefin) is comparable to the strain of the corresponding trans-cycloalkene from which it may be formally derived by bridging. This hypothesis, advocated by Wiseman in 1967 [3], has been supported by experimental evidence from a large number of synthetic approaches to different Bredt olefins and by two independent force-field calculations [4] [S].However, within a series of homologous bridged trans-cyclooctenes, truns-cycloheptenes, and trans-cyclohexenes, the principles which govern relative strain energies are not obvious. Kobrich [l] formulated a rule ('rule A'), according to which increasing the number of carbon atoms in the bridge should decrease the strain of the Bredt olefins. Indeed, whereas the ethylene-bridged truns-cyclo-

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Synthesis of .omega.-bromo ketones

Cited by 36 publications

References 8 publications

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.0^1,6]tetradecane

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.0^1,6]tetradecane

Regio‐ and Diastereoselective Conjugate Addition to 4,4‐Dimethylcyclohexadienones

Synthesis and Dimerization of Bicyclo [4.4.1] undec‐1 (11)‐ene, a Bridged trans‐Cycloheptene

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Synthesis of .omega.-bromo ketones

Cited by 36 publications

References 8 publications

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.01,6]tetradecane

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.01,6]tetradecane

Regio‐ and Diastereoselective Conjugate Addition to 4,4‐Dimethylcyclohexadienones

Synthesis and Dimerization of Bicyclo [4.4.1] undec‐1 (11)‐ene, a Bridged trans‐Cycloheptene

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A new synthesis of 2,10,11-trioxatricyclo[4.4.4.0^1,6]tetradecane

A new synthesis of 2,10,11-trioxatricyclo[4.4.4.0^1,6]tetradecane