A method for diastereoselective synthesis of unsaturated acyclic amines

Garigipati, Ravi S.; Morton, J. J.; Weinreb, Steven M.

doi:10.1016/s0040-4039(00)81583-x

Cited by 33 publications

(6 citation statements)

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“…The latter compound was then treated with sodium hydroxide followed by acidification to afford the corresponding sulfinic acid intermediate (462), which fragmented in refluxing chloroform to give amide 463 in good yield through a retro-sulfinyl-ene rearrangement. 204 The completion of the synthesis of 456 included a one-carbon homologation and the hydrogenolytic cleavage of the NsN bond to reveal the saturated piperidine moiety. A total synthesis of methyl palustramate (457) was reported using the same strategy and a novel hydrazine unit allowing a chemoselective NsN bond cleavage that left the alkene intact.…”

Section: Tandem Aza-[4 + 2]-cycloaddition/allylborationmentioning

confidence: 99%

Natural Product Synthesis Using Multicomponent Reaction Strategies

Touré¹,

2009

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Section: Tandem Aza-[4 + 2]-cycloaddition/allylborationmentioning

confidence: 99%

Natural Product Synthesis Using Multicomponent Reaction Strategies

Touré¹,

2009

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“…In situ desilylation and stereoselective desulfination via retro-ene elimination of SO 2 from the β,γ-unsaturated sulfinic acids 14' [53][54][55] generates, in a one-pot operation, compounds 15 containing up to three contiguous stereogenic centers and one (E)-alkene unit [52]. The polypropionate fragments 15 so-obtained have their two extremities ready for further chain elongation without requiring deprotection and activation.…”

Section: Introductionmentioning

confidence: 99%

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Vogel

Turks

Bouchez

et al. 2008

Pure and Applied Chemistry

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At low temperature and in the presence of an acid catalyst, SO 2 adds to 1,3-dienes equilibrating with the corresponding 3,6-dihydro-1,2-oxathiin-2-oxides (sultines). These compounds are unstable above -60°C and equilibrate with the more stable 2,5-dihydrothiophene 1,1-dioxides (sulfolenes). The hetero-Diels-Alder additions of SO 2 are suprafacial and follow the Alder endo rule. The sultines derived from 1-oxy-substituted and 1,3-dioxydisubstituted 1,3-dienes cannot be observed at -100°C but are believed to be formed faster than the corresponding sulfolenes. In the presence of acid catalysts, the 6-oxy-substituted sultines equilibrate with zwitterionic species that react with electron-rich alkenes such as enoxysilanes and allylsilanes, generating β,γ-unsaturated silyl sulfinates that can be desilylated and desulfinylated to generate polypropionate fragments containing up to three contiguous stereogenic centers and an (E)-alkene unit. Alternatively, the silyl sulfinates can be reacted with electrophiles to generate polyfunctional sulfones (one-pot, four-component synthesis of sulfones), or oxidized into sulfonyl chlorides and reacted with amines, then realizing a one-pot, four-component synthesis of polyfunctional sulfonamides. Using enantiomerically enriched dienes such as 1-[(R)-or 1-(S)-phenylethyloxy]-2-methyl-(E,E)-penta-1,3-dien-3-yl isobutyrate, derived from inexpensive (R)-or (S)-1-phenylethanol, enantiomerically enriched stereotriads are obtained in one-pot operations. The latter are ready for further chain elongation. This has permitted the development of expeditious total asymmetric syntheses of important natural products of biological interest such as the baconipyrones, rifamycin S, and apoptolidin A.

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“…As stated above, β,γ-unsaturated sulfinic acids are unstable at room temperature. They are formed as intermediates in the hydrolysis of sulfinamides, ,,− the reduction of β-ketosulfones, and the oxidation of allylic thiols . They have been proposed as intermediates in SO 2 -mediated alkene isomerization. ,,− As we have shown, this might not always be true .…”

Section: Introductionmentioning

confidence: 89%

“…In the case of α-substituted sulfinic acids 1 , a concerted retro-ene reaction (formally a retro hetero-Alder , ene reaction) that leads to the elimination of SO 2 is assumed to be responsible for the chirality transfer from the α-carbon center to the γ-carbon center with formation of alkenes 3 . The stereoselectivity of the reaction is explained in terms of a chairlike transition state 2 that places an optimal number of substituents in pseudoequatorial positions. − Kinetic investigations by Young and co-workers , on the desulfinylation of prop-2-enesulfinic acid in toluene were taken as consistent with a cyclic transition state ( k 297K = 5.5 ± 0.1) × 10 −4 s −1 , Δ S ‡ = −35 ± 4.5 e.u. ; Δ V ‡ = −5.5 ± 1.0 cm 3 /mol, Δ V r = 15 ± 5 cm 3 /mol).…”

Section: Introductionmentioning

confidence: 99%

Desulfinylation of Prop-2-enesulfinic Acid: Experimental Results and Mechanistic Theoretical Analysis

et al. 2009

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The potential energy surfaces of the desulfinylation of prop-2-enesulfinic acid (13) in CH(2)Cl(2) solution at -15 degrees C have been explored by quantum calculations and analyzed with kinetic data obtained for the reaction in absence or presence of additives. Monomeric 13 adopts a preferred conformation with gauche S=O/sigma(C(1)-C(2) bond pairs and the O-H bond pointing toward C(3). It equilibrates with the more stable dimer (13)(2) (at -15 degrees C) formed by two O-H...O=S hydrogen bonds and in which the S=O/sigmaC(1)-C(2) are gauche also, but the SOH moieties are antiperiplanar with respect to sigma(C(1)-C(2)). Dimer (13)(2) undergoes desulfinylation into propene + SO(2) + 13 following a one-step, concerted mechanism. The preferred transition state is a six-membered, chairlike transition structure (C...S elongation and S-O...H...C(3) hydrogen transfer occur in concert) in which the S=O/sigma(C(1)-C(2)) bonds are gauche (S=O adopt pseudoaxial positions). There are at least 48 transition states, each one defining a different pathway, all with similar calculated free energies (DeltaG(double dagger) = 25.3-28.6 kcal/mol), which makes the bimolecular (autocatalyzed) retro-ene elimination of SO(2) competing (entropy factor) with a monomolecular process for which the transition state (calculated DeltaG(double dagger) = 24.3 kcal/mol) implies only one molecule of sulfinic acid. This agrees with the experimental rate law of the reaction which is first order in the concentration of dimer (13)(2). SO(2), CF(3)COOH, and BF(3) x Me(2)O do not catalyze the reaction. In the presence of an excess of BF(3) x Me(2)O the desulfinylation is completely inhibited due to the formation of a stable tetramolecular complex of type (CH(2)=CHCH(2)SO(2)H x BF(3))(2) (18), for which quantum calculations show that the S=O/sigma(C(1)-C(2)) bonds are antiperiplanar whereas the S-OH/sigma(C(1)-C(2)) bonds are gauche. Independently of the additive, the retro-ene eliminations of SO(2) are calculated to be concerted and have transition states adopting six-membered cyclic structures in which S=O and sigma(C(1)-C(2)) are gauche, the S=O interacting with the additive. Preliminary experiments suggested that the thermodynamically unfavored ene reaction of SO(2) with propene can occur at low temperature using 1 equiv of BF(3).

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A method for diastereoselective synthesis of unsaturated acyclic amines

Cited by 33 publications

References 10 publications

Natural Product Synthesis Using Multicomponent Reaction Strategies

Natural Product Synthesis Using Multicomponent Reaction Strategies

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Desulfinylation of Prop-2-enesulfinic Acid: Experimental Results and Mechanistic Theoretical Analysis

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