Unexpected behavior of an .alpha.-tosyloxy sulfone compared with an .alpha.-chloro sulfone in base-induced reactions

Meyers, Cal Y.; Hua, Duy H.; Peacock, Nancy J.

doi:10.1021/jo01297a052

Cited by 16 publications

(1 citation statement)

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“…iodide, [1][2][3][4][5][6]10,11] sulfonate [1][2][3][4][5][6]12] and sulfinate [1][2][3][4][5][6][13][14][15][16][17] esters have all been used successfully in Ramberg-Bäcklund-type reactions, not a great deal of research into the use of different leaving groups in this process has been reported.…”

Section: Introductionmentioning

confidence: 99%

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

2006

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Section: Introductionmentioning

confidence: 99%

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

2006

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The Ramberg‐Bäcklund Reaction

Taylor

Casy

2003

Organic Reactions

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The base‐mediated conversion of alpha‐halosulfones into region‐defined alkenes was first described by Ludwig Ramberg and Birger Backlund. This transformation has proved to be of wide synthetic value and is known as the Ramberg‐Backlund reaction (RBR). The facile nature of the RBR is surprising given the difficulties encountered when attempting to carry out nucleophilic substitution reactions on alpha‐halosulfones. In contrast to halogens adjacent to carbonyls and related electron‐withdrawing groups, polar, steric and field effects appear to combine leading to the marked deactivation of alpha‐halosulfones. The stereochemical outcome of the reaction was also unexpected: a predominance of Z‐alkenes is often observed with relatively weak bases, whereas stronger bases tend to favor E‐alkenes. The mechanism of the RBR was therefore the subject of intense interest, particularly in the 1950s and 1960s. From the synthetic viewpoint, the RBR is attractive for a number of reasons, for example, the accessibility of the precursor sulfide and sulfones; the conjunctive nature of the process; the unambiguous location of the resulting double bonds, among others. Organic sulfones are readily available, but the preparation of alpha‐halosulfones can be problematic. In view of this, perhaps the most significant synthetic advance concerning RBR has been the development of Meyer's modification, which involves in‐situ halogenation‐RBR sequence and enables sulfones to be converted directly into alkenes. This chapter discusses the mechanism of RBR, its scope and limitations, applications of the reaction in natural product synthesis, and comparison of the RBR with related procedures. Representative experimental procedures are also given.

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Reaktion von Azibenzilen mit Nonafluorbutansulfonsäureanhydrid

Lorenz

Maas

1986

Chem. Ber.

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Die Azibenzile l a -e reagieren mit Nonafluorbutansulfonsaureanhydrid (Nf20) hauptsachlich zu den Vinylen-bis(nonafluorbutansu1fonaten) E,Z-ta -e und den Benzilen 3a -e. Um die Zersetzung der Azibenzile durch Saurespuren im Anhydrid zu vermeiden, ist der Zusatz eines nicht nucleophilen Amins erforderlich. Die Produkte 2 gehen aus einer einleitenden 0-Sulfonylierung der Azibenzile hervor, fur die Bildung der Benzile konnte eine C-Sulfonylierung verantwortlich sein. Diazodiphenylmethan wird durch Nf20 zu Tetraphenylethylen, Benzophenon und Benzophenon-azin zersetzt. Reaction of Azibenzils with Nonafluorobutanesulfonic AnhydrideReaction of azibenzils 1 a -e with nonafluorobutanesulfonic anhydride (Nf20) yields mainly vinylene bis(nonafluorobutanesu1fonates) E.Z-2a -e and benzils 3a-e. The presence of a non-nucleophilic amine prevents decomposition of the azibenzils by traces of acid in the anhydride. Compounds 2 stem from an initial 0-sulfonylation of the azibenzils, whereas C-sulfonylation perhaps leads to the benzils. Diazodiphen ylmethane is decomposed by Nf20 to give tetraphenylethylene, benzophenone, and benzophenone azine.Wir haben kurzlich dariiber berichtet, daB Azibenzile mit Trifluormethansulfonsaureanhydrid unter einleitender 0-Tdluormethansulfonylierung reagieren 'I. Uber P-Trifloxyalkendiazonium-Ionen und Vinylkationen als Zwischenstufen kommt es letztendlich zur Bildung von Vinylen-bis(trifluormethansu1fonaten) (Schema 1). Schema I

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Unexpected behavior of an .alpha.-tosyloxy sulfone compared with an .alpha.-chloro sulfone in base-induced reactions

Cited by 16 publications

References 0 publications

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

The Ramberg‐Bäcklund Reaction

Reaktion von Azibenzilen mit Nonafluorbutansulfonsäureanhydrid

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