Mechanism of the nitrous acid-induced dealkylation of trisubstituted (terminal isopropylidene) olefins to form acetylenes

Corey, E. J.; Seibel, William; Kappos, John C.

doi:10.1016/s0040-4039(00)96659-0

Cited by 31 publications

(10 citation statements)

References 16 publications

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“…Sometime later, the group of Corey disclosed the results of their extensive study of this strange reaction. 3 Although they could reproduce the transformation in the case of geraniol, the yield of alkyne remained low, ranging from 25 to 33%, quite at variance with the staggering 98% yield claimed by Abidi. The reason for the large difference in the yield is not yet clear.…”

Section: A Very Strange Reactionmentioning

confidence: 91%

“…The feasibility of the sequence going from compound 8 to the alkyne 2 was tested with success on a model structure. 3 The only part of the proposed mechanism for which no experimental support could be provided concerned the conversion of the primary nitro group in 4 into aldehyde 5.…”

Section: A Very Strange Reactionmentioning

confidence: 99%

“…It turns out that the carboxylic acid analog 13 of the putative intermediate aldehyde 5 does not proceed to alkyne 14 under the Abidi conditions. 3 The section of the proposed mechanism connecting allylic nitro 3 with intermediate 8 remained therefore unsettled.…”

Section: A Very Strange Reactionmentioning

confidence: 99%

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New syntheses of alkynes: a tale of serendipity and design

Zard

2002

Chem. Commun.

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Section: A Very Strange Reactionmentioning

confidence: 91%

Section: A Very Strange Reactionmentioning

confidence: 99%

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New syntheses of alkynes: a tale of serendipity and design

Zard

2002

Chem. Commun.

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“…In 1985, Abidi 62 reported an unusual transformation of the isopropylidene fragment of linear monoisoprenoid derivatives into a methylethynyl fragment, which occurred upon treatment with NaNO 2 in aqueous acetic acid (see also the subsequent papers by Abidi 63,64 ). It should be noted here that later studies of this reaction (formal methane elimination) with the same and related substrates 65,66 could not reproduce the previously reported 62 ± 64 high yields (60% ± 90%) of the corresponding methylacetylenes 65a ± g. For example, the yield of the acetylene 65e from geraniol was no higher than 35%. 65 It was found that this reaction initially yields the nitro derivative 66.…”

Section: Reactions Involving Nitrous Acid Saltsmentioning

confidence: 55%

Reactions of alkenes with nitrogen oxides and other nitrosating and nitrating reagents

Степанов¹,

Veselovsky²

2003

Russ. Chem. Rev.

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We present a theory of light amplification in a cavity based on irreversibility of coherent excitation. It is predicted that the irreversibility of coherent excitation leads to a new way of lasing which is different from lasing with and without inversion in the conventional sense. Lasing with dynamically induced inversion is possible in coherently driven systems in which there is no conventional source of irreversible population pumping. This laser displays two interesting and important features: the maximum gain with inversion is substantially greater than gain without inversion, and in spite of the presence of the inversion, the noise intensity is reduced below the shot-noise limit.As is well known, atomic transitions arise in two ways: they can occur spontaneously as a consequence of the atom's coupling to the vacuum, or they can be stimulated by external perturbation such as a laser field. Usually, the spontaneous transition is referred to as spontaneous emission, spontaneous decay, etc, while the stimulated transition is known as coherent excitation, coherent driving, coherent coupling, etc. The spontaneous transitions are irreversible since they occur from states of higher energy to states of lower energy. The stimulated transitions, however, are reversible, i.e. the probabilities of photon absorption and emission are equal. As a result, it is impossible to achieve steady-state population inversion in a driven two-level atom. It is a widely held view that, in order to create the population inversion required to achieve light amplification, one has to utilize the irreversible transition as a population pump in a multilevel system.Recently, the new concept of lasing without inversion has received much attention (see [1] for reviews). It has been shown that, in cases where it is difficult or even impossible to create the required population inversion via conventional pumping, lasing without inversion provides an important and interesting alternative. It is identified that the origin of the inversionless gain is attributed to either inversion between dressed states or coherence among these states [2]. The inversionless gain has been demonstrated [3] and the first lasers without inversion have been realized [4]. In addition, dressed-state lasers belong to the class of lasers without inversion since there is no inversion between bare atomic states. The idea stems from Mollow [5], who predicted that a strongly driven two-level atom can amplify a weak probe beam at one of the Rabi sideband frequencies. The gain is due to population inversion between dressed states [6]. As will be shown, however, lasing without inversion is not the only option when it is difficult or impossible to provide the required population inversion using conventional pumping.In this letter, we will present a theoretical analysis of light amplification in a cavity, based on irreversibility of coherent excitation. It is predicted that lasing with inversion is possible 0953-4075/00/070265+10$30.00

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“…with the 25-33% yield Corey et al 31 and the 10-15% yield Zard and co-workers 32 had obtained in their mechanistic studies of the reaction, we isolated 3-methyloct-6yn-1-ol (20) in 26% yield after chromatographic purification (Scheme 2). The mechanism of this unusual demethylation is believed to involve an N-hydroxypyrazole N-oxide, which is further nitrosated.…”

Section: Figurementioning

confidence: 98%

(4E,8Z)-12-Methyloxacyclotetradeca-4,8-dien-2-one and Its 7a-Homologue: Conformationally Constrained Double-Unsaturated Macrocyclic Musks by Ring-Closing Alkyne Metathesis

Kraft¹,

Berthold²

2008

Synthesis

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The double-unsaturated macrocyclic lactones (4E,8Z)-12-methyloxacyclotetradeca-4,8-dien-2-one and its 7a-homologue (4E,9Z)-13-methyloxacyclopentadeca-4,9-dien-2-one, designed as new potent musk odorants by molecular modeling, were synthesized by ring-closing alkyne metathesis in the presence of 10 mol% of Schrock's alkylidyne catalyst, and subsequent Lindlar hydrogenation. Demethylation of citronellol, induced by nitrous acid, afforded the 3-methyloct-6-yn-1-ol building block. The substrates for the alkyne metathesis were prepared by Steglich esterification of citronellol with the 3E-configured non-3-en-7-ynoic and dec-3-en-8-ynoic acids, accessible by b,g-selective Knoevenagel condensation from the corresponding alkynals hept-5-ynal and oct-6-ynal, which were synthesized by Eschenmoser-Ohloff fragmentation of the epoxide of 2-methylcyclohex-2-enone, and methylation of hex-5-yn-1-ol, respectively. Both target structures, (4E,8Z)-12-methyloxacyclotetradeca-4,8-dien-2-one and its 7a-homologue, emanated most pleasant and powerful musk odors.

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Mechanism of the nitrous acid-induced dealkylation of trisubstituted (terminal isopropylidene) olefins to form acetylenes

Cited by 31 publications

References 16 publications

New syntheses of alkynes: a tale of serendipity and design

New syntheses of alkynes: a tale of serendipity and design

Reactions of alkenes with nitrogen oxides and other nitrosating and nitrating reagents

(4E,8Z)-12-Methyloxacyclotetradeca-4,8-dien-2-one and Its 7a-Homologue: Conformationally Constrained Double-Unsaturated Macrocyclic Musks by Ring-Closing Alkyne Metathesis

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