Synthesen in der Carotinoid‐Reihe. 10. Mitteilung. Anwendung der <i>Wittig</i>‐Reaktion zur Synthese von Estern des Bixins und Crocetins

Isler, O.; Gutmann, Heike; Montavon, M.; Rüegg, R.; Ryser, G.; Zeller, P.

doi:10.1002/hlca.19570400515

Cited by 337 publications

(48 citation statements)

References 6 publications

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“…An analogous reaction has already been carried out with tetrahydro-2-pyranol (16). Treatment of the 2-chromanols with ethyl (triphenylphosphorany1idene)acetate in benzene or dimethylformamide ( 16,17) gave the 5-(0-hydroxypheny1)-2-pentenoic esters 26-28. In all cases the E isomer was the major product; this was obtained in admixture with a small amount of the Z isomer and the by-product, triphenylphosphine oxide.…”

mentioning

confidence: 99%

Tandem Wessely oxidation and intramolecular Diels–Alder reactions. III. Synthesis of isotwistanes

Yates¹,

Macas²

1988

Can. J. Chem.

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PETER YATES and TADAS S. MACAS. Can. J. Chem. 66, 1 (1988).Wessely oxidation of o-(3-alkenyl) phenols (5) with lead tetraacetate gives 6-acetoxy-6-(3-atkeny1)-2,4-cyclohexadien-I-ones (6), which undergo intramolecular Diels-Alder reactions to give isotwistene (hexahydro-1.5-methanoindene) derivatives (7). These, on hydrolysis followed by oxidation with periodic acid, give hexahydro-1-0x0-l H-indene-5-carboxylic acids (41, 46). Compounds 5 were prepared either by Grignard coupling of o-methoxybenzyl chloride with ally1 halides followed by de-0-methylation with sodium thioethoxide or via reduction of dihydrocoumarins (18-20) to 2-chromanols (21-23) with diisobutylaluminum hydride, followed by Wittig reaction of these with ethyl (triphenylphosphoranylidene)acetate. The oxidation of ortho-substituted phenols with lead tetraacetate LTA to give 6-acetoxy-2,4-cyclohexadien-1-ones (oquinol acetates; I ) , which was first reported by Wessely and his co-workers in 1950 (4), is the simplest general method for the synthesis of the latter class of compounds. Wessely early recognized (5) the potential utility of o-quinol acetates in intermolecular Diels-Alder reactions leading to bicyclo[2.2.2]octenones and bicyclo[2.2.2]octadienones (e.g., 2 (R = CH3) 3, (Scheme 1).Work in these laboratories (1, 2) has shown that an intramolecular version of the latter reaction can be effected by Wessely oxidation products that incorporate a dienophilic group in the ester moiety (e.g., 3). This provides a route to tricyclic lactones of type 4, as exemplified in Scheme 2.It occurred to us that a related reaction sequence involving Wessely oxidation of an o-(3-alkenyl) phenol (5) to give a 2,4-cyclohexadienone of type 6, followed by intramolecular cyclic analogues of 4, i.e., isotwistene (hexahydro-l,5-methanoindene) derivatives of type 7 (Scheme 3). Other workers (7) have already demonstrated the practicability of the synthesis of tricyclic systems via intramolecular reactions of alkenyl 1,3-cyclohexadiene derivatives, but none to our knowledge has coupled this reaction with the Wessely oxidation reaction. Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.213.91.117 on 05/10/18For personal use only.

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Tandem Wessely oxidation and intramolecular Diels–Alder reactions. III. Synthesis of isotwistanes

Yates¹,

Macas²

1988

Can. J. Chem.

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“…The starting material estrone (1) (Wako Pure Chemical Industries, Ltd.) was used as purchased. 3-Methoxyestra-1,3,5(10)-trien-3-one (2a) (KOH, MeI, DMSO), 3-Benzyloxyestra-1,3,5(10)-trien-3-one (2b) (BnBr, NaH, dry DMF), O-protected 17-bromo-3-hydroxyestra-1,3,5(10),16-tetraen-16-carbaldehydes (3a-c) [19] ethoxy-and methoxycarbonylmethylidenetriphenylphosphorane (6a) [26] and (6d), acetylmethylidenetriphenylphosphorane (6b) [27] and benzoylmethylidenetriphenylphosphorane (6c) [27] were synthesized according to procedures published in the literature. 8d is a known compound [19].…”

Section: Generalmentioning

confidence: 99%

Heteroareno-annelated estranes by triene cyclization

et al. 2006

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“…Acrolein (10.36 g, 0.185 mol) was added dropwise to a stirred carbamoylmethylenetriphenylphosphorane (67.07 g, 0.193 mol) 12 in dry THF (350 mL) at room temperature. The mixture was refluxed for 24 h and concentrated.…”

Section: Synthesis Of Ethyl 24-pentadienoatementioning

confidence: 99%

Synthesis of polymers containing conjugated dienyl end-groups by means of anionic living polymerization

Mizawa

Takenaka

Shiomi

1999

J. Polym. Sci. A Polym. Chem.

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Synthesen in der Carotinoid‐Reihe. 10. Mitteilung. Anwendung der Wittig‐Reaktion zur Synthese von Estern des Bixins und Crocetins

Cited by 337 publications

References 6 publications

Tandem Wessely oxidation and intramolecular Diels–Alder reactions. III. Synthesis of isotwistanes

Tandem Wessely oxidation and intramolecular Diels–Alder reactions. III. Synthesis of isotwistanes

Heteroareno-annelated estranes by triene cyclization

Synthesis of polymers containing conjugated dienyl end-groups by means of anionic living polymerization

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