Transformed steroids. 180. Stereospecific transformation of 17?-hydroxy-17?-ethynylsteroids into various 17?-substituted 17?-ethynylsteroids

Turuta, A. M.; Фадеева, Т. М.; Камерницкий, А. В.; Korobov, A. A.; Cherepanova, E. G.; Khu, L'yru Dyk

doi:10.1007/bf00959591

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…The stereochemical outcome of this reaction results from the transient formation of a carbocation with a subsequent hydride attack occurring via the less hindered α side. This approach was later extended to synthesis of compounds of type 669 , prepared by addition of various nucleophiles on the in-situ-formed carbocation derived from dehydration of 668 (Scheme ) . The byproduct 671 also formed during these transformations (up to 50%).…”

Section: Nonbiological Developmentsmentioning

confidence: 99%

Synthesis of Transition-Metal Steroid Derivatives

Bideau

Dagorne

2013

Chem. Rev.

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Section: Nonbiological Developmentsmentioning

confidence: 99%

Synthesis of Transition-Metal Steroid Derivatives

Bideau

Dagorne

2013

Chem. Rev.

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“…[8] Moreover, early reports [6] on propargyl isothiocyanates 3aϪe and allenyl thiocyanates 4c and 4d arrived at the conclusion that the sigmatropic migration is always an irreversible process favoring 3 (Table 1). Scheme 2.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of New Vinyl Thiocyanates by [3,3] Sigmatropic Rearrangement of Isothiocyanates

2001

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Keywords: Alkynes / Allenes / Dienes / Isothiocyanates / Rearrangements / ThiocyanatesPropargyl isothiocyanates 3 and buta-2,3-dienyl isothiocyanates 20 were prepared conventionally from amines and thiophosgene, or by a new, one-pot procedure using nucleophilic substitution to generate azides, which in turn served as the starting materials for a Staudinger reaction, followed by treatment of the resulting iminophosphoranes or iminophosphates with CS 2 . Equilibration, through a [3,3] sigmatropic rearrangement, of 3 and the allenyl thiocyanates 4 was established by flash vacuum pyrolysis or by thermolysis in solution. Even the reversible isomerization of the parent compounds 3f and 4f favors the allenyl thiocyanate. In the case of 20, an irreversible rearrangement reaction gave high yields of 2-thiocyanatobuta-1,3-dienes 21. A sequence of two [3,3] migration steps transformed 1,4-diisothiocyanatobut-2-ynes 3m and 3n into 2,3-dithiocyanatobuta-1,3-di-

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Rearrangement Reactions, 6. New Functionalized Allenes: Synthesis Using Sigmatropic Rearrangements and Unusual Reactivity

Banert

1997

Liebigs Ann./Recl.

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The present article summarizes the synthesis of allenes, which bear a functional group with at least two heteroatoms, by [2,3] or [3,3] sigmatropic rearrangements of appropriate propargyl precursors. Recently, this method has been extended to prepare new types of functionalized allenes such as isocyanates, isothiocyanates, isoselenocyanates, azides, thiocarbonates, and azo compounds. The title compounds are very reactive as shown by rapid intra-and intermolecular consecutive reactions. This reactivity can be used to synthesize heterocycles and doubly functionalized 1,3-butadienes.

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Transformed steroids. 180. Stereospecific transformation of 17?-hydroxy-17?-ethynylsteroids into various 17?-substituted 17?-ethynylsteroids

Cited by 5 publications

References 9 publications

Synthesis of Transition-Metal Steroid Derivatives

Synthesis of Transition-Metal Steroid Derivatives

Synthesis of New Vinyl Thiocyanates by [3,3] Sigmatropic Rearrangement of Isothiocyanates

Rearrangement Reactions, 6. New Functionalized Allenes: Synthesis Using Sigmatropic Rearrangements and Unusual Reactivity

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