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Ring Expansion into Four-Membered Heterocycles

Ring Expansion into Four-Membered Heterocycles [Pg.88]

A general method has been elaborated for the synthesis of oxetanes from oxiranes by means of carbene insertion, with an a-selenoalkyllithium reagent that has also been utilized for the regioselective preparation of the oxirane itself from a carbonyl compound (Eq. 185).  [Pg.88]

Oxetanes can similarly be produced from oxiranes by using an excess of dimethyl-A -(p-toluenesulphonyl)sulfoxime reagent (Eq. 186).  [Pg.89]

Oxetanes are formed by intramolecular ring-closure of 3,4-epoxy alcohols and their methyl analogues in basic medium. The alkoxide anion attacks regioselectively on atom C-3 (Eq. [Pg.89]

The stereochemistry of the reaction has been studied in rigid and in nonrigid systems. A new route to functionalized 1,2-dioxetanes has been described. Lactones can be obtained by oxidation of the intermediate complex formed from dienemonooxiranes by carbonyl group insertion with pentacarbonyliron (Eq. 188).  [Pg.89]

B. Ring Expansion into Four-Membered Heterocycles... [Pg.88]

See other pages where Ring Expansion into Four-Membered Heterocycles is mentioned: [Pg.104]    [Pg.180]    [Pg.88]    [Pg.88]    [Pg.104]    [Pg.37]    [Pg.3]   


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