Iodocyclization of the (tolylsulfonyl)- and (trichloroacetyl)carbamates of secondary .alpha.-allenic alcohols. Highly diastereoselective synthesis of syn-1,2-amino alcohols and trans-5-alkyl-1-oxo-2-oxazolidine-4-carboxylic acids

Friesen, Richard W.; Kolaczewska, A. E.

doi:10.1021/jo00016a016

Cited by 34 publications

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“…Thus, treatment of 4b with N-bromosuccinimide (NBS) in dichloromethane 14 provided the bicyclic urethane 5a in good yield. Similarly, reaction of 4b with iodine in diethyl ether 15 gave the corresponding iodo compound 5b. 5…”

Section: Methodsmentioning

confidence: 98%

Synthesis of Cyclohexenylamines by Ring Closing Metathesis

Maier¹,

Lapeva²

1998

Synlett

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Starting from 5-pentenaldehyde 1, the 1-allyl-4-pentenylamines 2a-d were prepared. The ring closing metathesis reaction of these dienes using the Grubbs catalyst 3 gave the corresponding cyclohexenylamines 4a,b and 4d in high yield. The secondary amine 2c was recovered unchanged. This route to compound 4d represents a formal total synthesis of the alkaloid epibatidine. In addition, 4b was transformed by electrophilic transannular cyclization to the bicyclic urethanes 5a and 5b.The ring-closing metathesis (rcm) is one of a few reactions that form a double bond in the cyclization step. In contrast to the intramolecular Wittig reaction or the McMurry cyclization, the starting materials, acyclic nonconjugated dienes, are stable entities and usually easily accessible. It is thus logical that the rcm reaction has found widespread use 1 since the discovery of carbene complexes that are able to mediate this reaction efficiently. In addition, some of these complexes are easily available. 2 The rcm reaction allows the formation of cyclic olefins with various ring sizes. However, as with other cyclization reactions, entropic factors and ring strain make the formation of medium-sized cycloolefins by this route difficult. Other well-known ways to some cyclic olefins include cycloaddition reactions. While, for example, cyclohexenes can be obtained by Diels-Alder reactions, not all substitution patterns are suitable for this strategy. Examples include cyclohexenes with a hetero atom at the homoallylic position. They require the use of special dienophiles, such as vinylboranes 3 or rearrangement reactions on a carboxylic substituent. 4 Such cyclohexenes are of interest for the synthesis of bicyclic heterocycles by transannular reactions (Scheme 1). In this paper we show that for cyclohexenyl amines the rcm reaction represents a useful alternative to the Diels-Alder strategy. Scheme 1The corresponding substrates, 1-allyl-4-pentenylamines should be available by addition of an allyl anion equivalent to a suitable 4-pentenylimine. According to this strategy, the 1,7-octadien-4-amine derivatives 2a-d were prepared. 5 The urethanes 2a,b were synthesized in analogy to a published procedure. 6 Thus, addition of boron trifluoride etherate to a mixture of 4-pentenal, 7 benzyl carbamate and allyl(trimethyl)silane followed by stirring of the reaction mixture over night gave the urethane 2a in 60% yield. In a similar manner the urethane 2b was prepared by using tert-butyl carbamate instead. No product was obtained with trifluoroacetamide (Scheme 2).It was also of interest to study the influence of substituents at the amino function upon the rcm reaction. Therefore, the secondary amine 2c was synthesized in a simple two-step operation by first converting the aldehyde 1 with benzylamine to the corresponding imine followed by addition of allyl(tributyl)stannane and trifluoroacetic acid. 8,9 Treatment of the benzyl amine 2c with trifluoroacetic anhydride in the presence of triethylamine furnished the protected aminodiene 2d. Scheme 2The crucial...

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Section: Methodsmentioning

confidence: 98%

Synthesis of Cyclohexenylamines by Ring Closing Metathesis

Maier¹,

Lapeva²

1998

Synlett

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“…1‐Cyclohexyl‐2,3‐butadien‐1‐ol (2l): The reaction of CuI (190.6 mg, 1.00 mmol), paraformaldehyde (480.7 mg, 16.01 mmol), 1l (1.3827 g, 10.00 mmol), and i Pr 2 NH (2.0 mL, d = 0.716 g mL –1 , 1.432 g, 14.15 mmol) in dioxane (15 mL) afforded 2l 11d (1.2546 g, 82 %) after purification (eluent for chromatography: petroleum ether/ethyl acetate, 5:1) as a liquid. 1 H NMR (300 MHz, CDCl 3 ): δ = 5.21 (q, J = 6.6 Hz, 1 H, C=CH), 4.82 (dd, J = 6.8, 2.2 Hz, 2 H, C=CH 2 ), 3.97–3.86 (m, 1 H, OCH), 1.90–1.58 (m, 6 H, Cy), 1.49–1.34 (m, 1 H, OH), 1.31–0.91 (m, 5 H, Cy) ppm.…”

Section: Methodsmentioning

confidence: 99%

CuI‐Catalyzed Synthesis of Functionalized Terminal Allenes from 1‐Alkynes

Luo

2013

Eur J Org Chem

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Relative to our original protocol that uses CuI (0.5 equiv.), paraformaldehyde (2.5 equiv.), and dicyclohexylamine (1.8 equiv.), a facile and efficient protocol for the gram‐scale synthesis of functionalized terminal allenes by using CuI (7.5–10 mol‐%), paraformaldehyde (1.6 equiv.), and diisopropylamine (1.4 equiv.) has been developed. This method accommodates different functional groups such as hydroxy or carbonyl, and it also performed well in the synthesis of allenylamides and 2,3‐butadien‐1‐ol.

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“…Allylation Products. Homoallylic, -allenic, and -propargylic alcohols ( 5 − 8 , 10 − 13 , and 18 − 33 ) obtained herein were characterized by 1 H and 13 C NMR spectroscopy, microanalysis, and high-resolution mass spectrometry (where appropriate), and by comparison with literature values: 5a , 5b , 5d , 5f , 6a ,18b 7a ,18b 6b , 7b , 6c , 7c , 6d , 7d , 6f , 7f , 8a ,18a 8b , 8d , , 8f , 11 , 12 , 18a , 19a , 18c , 19c , 18d , 20a, 19d , 20a, 18e , 19e , 20c , 21c , 20d , 21d , 24d , 25d , 26b , 27b , 28b , 29b …”

Section: Methodsmentioning

confidence: 99%

A Highly Atom Efficient, Solvent Promoted Addition of Tetraallylic, Tetraallenic, and Tetrapropargylic Stannanes to Carbonyl Compounds

et al. 2001

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Tetraallylic, tetraallenic, and tetrapropargylic stannanes (0.25 equiv) react with aldehydes in methanol to provide unsaturated alcohols in good to excellent yields (56-99%). These reactions proceed exclusively with allylic rearrangement for tetra(2-butenyl)tin 2b and tetra(1,2-butadienyl)tin 16c and predominantly with allylic rearrangement for tetrapropadienyltin 16a and tetra(2-butynyl)tin 6e. Allylation reactions also proceeded smoothly with reactive ketones such as ethyl pyruvate (9a) and cyclohexanone (9b). The corresponding TFA-catalyzed reactions of dimethyl acetals 4d and 4e are regiospecific with allylic rearrangement.

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Iodocyclization of the (tolylsulfonyl)- and (trichloroacetyl)carbamates of secondary .alpha.-allenic alcohols. Highly diastereoselective synthesis of syn-1,2-amino alcohols and trans-5-alkyl-1-oxo-2-oxazolidine-4-carboxylic acids

Cited by 34 publications

References 0 publications

Synthesis of Cyclohexenylamines by Ring Closing Metathesis

Synthesis of Cyclohexenylamines by Ring Closing Metathesis

CuI‐Catalyzed Synthesis of Functionalized Terminal Allenes from 1‐Alkynes

A Highly Atom Efficient, Solvent Promoted Addition of Tetraallylic, Tetraallenic, and Tetrapropargylic Stannanes to Carbonyl Compounds

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