Ring cleavage reductive

Irradiation of 3,5-disubstituted isoxazoles in alcoholic solvents gave reaction products such as acetals incorporating the reaction solvent. The use of triethylamine in acetonitrile media produced ketene-aminals by reductive ring cleavage. The reductive ring cleavage product was also obtained by irradiation of the isoxazole in alcohol in the presence of copper(II) salts (Scheme 3) (76JCS(P1)783). 

Another mode of reductive ring cleavage is observed for 4-phenylazetidin-2-ones. These undergo N(l)—C(4) bond fission on hydrogenolysis in the presence of Raney nickel to yield the corresponding 3-phenylpropanamides (75S547 p. 583). 

Azetidin-2-one, l-benzyl-3,3,4-triphenyl-, 7, 249 Azetidin-2-one, l-(2-bromophenyl)-X-ray crystallography, 7, 247 Azetidin-2-one, 3-carboxy-synthesis, 7, 262 Azetidin-2-one, 3-halo-synthesis, 7, 77 ring contraction, 7, 81-82 Azetidin-2-one, 4-imino-IR spectroscopy, 7, 248 Azetidin-2-one, 1-phenyl-irradiation, 7, 255 Azetidin-2-one, 4-phenyl-reductive ring cleavage, 7, 252 Azetidin-2-one, 4-thio-IR spectroscopy, 7, 248 Azetidinones bicyclic, 7, 348-356 C NMR, 7, 348 H NMR, 7, 348 reactivity, 7, 356-358 spectroscopy, 7, 357 structure, 7, 349 synthesis, 7, 358-359 fused ring... 

Hydrogenation/Reduction/Reductive Ring Cleavage of the N-0 Bond, 6.2 Hydroxylation of the Ring Carbon-Carbon Double Bond/Oxidation, 6.3 Ozonolysis. 6.4 Epoxidation... 

Hydrogenation/Reduction/Reductive Ring Cleavage of the N-0 Bond... 

By lithium aluminum hydride. The reaction at several dpi-sulfides with lithium aluminum hydride has been shown to proceed with reductive ring cleavage to give thiols as their lithium mercaptidea in about 75% yields. The secondary thiols, rather than the corresponding 1 -thiols, wore obtained from the reduction of propylene sulfide and 1-hexene sulfide ... 

Reactions and reductive ring cleavage 6.06.5.3.4 Reductive ozonolysis with aminoxides... 

TrioxoIanes and 1,2,4-trioxoIanes react with C-nucIeophiles such as Grignard reagents or organolithium compounds, resulting, as with various other reductants, in reductive ring cleavage (see Section 4.33.3.3.6). 

On reaction with sodium iodide in glacial acetic acid, 1,2,4-trioxolanes undergo a reductive ring cleavage which will be discussed in Section 4.33.3.3.6. In the presence of potassium fluoride, 5,5-difluoro-l,2,4-trioxolan-3-one (136) isomerized at low temperatures to give bis(fluoroformyl) peroxide (137). Since the reaction is reversible (cf. Section 4.33.4.2.5), isomerization occurred with an equilibrium being established (72IC2531). 

Better results are obtained with ruthenium complexes of the corresponding thiono-lactones. Reductive ring cleavage with LiAlH4, then methylation and decomplexation, leads to the thioether (76 % ee). The chiral ruthenium complex recovered in this step can be converted back into the starting complex in two steps (Sch. 7) [55]. 

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