Ketoxime sulfonate

N.S. Mani and co-workers utilized the organoaluminum promoted modified Beckmann rearrangement during their efficient synthetic route to chiral 4-alkyl-1,2,3,4-tetrahydroquinoline. (4R)-4-Ethyl-1,2,3,4-tetrahydroquinoline was obtained by rearrangement of the ketoxime sulfonate of (3R)-3-ethylindan-1-one. The resulting six-membered lactam product was reduced to the corresponding cyclic secondary amine with diisobutylaluminum hydride. 

Ooi, T., Takahashi, M., Doda, K., Maruoka, K. Asymmetric Induction in the Neber Rearrangement of Simple Ketoxime Sulfonates under Phase-Transfer Conditions Experimental Evidence for the Participation of an Anionic Pathway. J. Am. Chem. Soc. 2002, 124, 7640-7641. 

By means oforganocatalytic methods, it is also possible to synthesize 2 H-azirines, which are the smallest heterocycle containing a C=N in a three-membered ring, and which occur in some natural products. For this purpose, the Neber reaction of several P-ketoxime sulfonates 16 catalyzed by thiourea 17 was carried out, giving the corresponding 2H-azirines 18 with good results (Scheme 27.6) [17]. This reaction was applied as a key step in the synthesis of the antipode of natural dysidazir-ine, which was achieved in five steps with 75% yield and 93% ee. 

The scope of the above is rather limited, mainly because of the need to prepare the starting ketoximes 222 and the resultant specific pattern of the sulfone product. 

The reaction is reversible, but the state of equilibrium highly favors the desired products. Preparations of large quantities for synthetic work are illustrated for methyl ethyl ketoxime, cyclohexanone oxime, hept-aldoxime, and benzophenone oxime, the procedures varying somewhat with the nature of the carbonyl compound. In some instances, a readily available and cheap reagent like sodium hydroxylamine disulfonate, HON(SO,Na)j, is first prepared from sodium nitrite and sodium bisulfite and, without isolation, treated with the carbonyl compound, Hydioxylamine-O sulfonic add, Ii,NOSO,H, is still another reagent and, like sodium hydroxylamine disulfonate, is used in the absence of a base. The preparation of hydroxylamine hydrochloride is described. ... 

O Brien, C. The rearrangement of ketoxime 0-sulfonates to amino ketones (The Neber rearrangement). Chem. Rev. 1964, 64, 81-90. 

Neber rearrangement. Formation of a-amino ketones by treatment of sulfonic esters of ketoximes with potassium ethoxide, followed by hydrolysis. 

The Neber rearrangement650-653 is a method for preparing a-amino ketones by base-catalyzed intramolecular rearrangement of ketoxime O-sulfonates. The intermediate azirine,654-656 which can be isolated, can also lead to aziridine derivatives when the base is lithium aluminum hydride657 or a Grignard reagent (the Hoch-Campbell reaction)658,659 (Eq. 190). 

Epoxycycloliexane, 126 a,/3-Epoxy esters, 258 Epoxy ketones, 166, 245, 343 a,i3-Epoxy ketoximes, 505 Epoxy mesylates, 15-16 a,/3-Epoxysilanes, 277-278 a,/3-Epoxy sulfones, 340 a-Epoxy sulfoxides, 95 Ergosterol, 435, 436 Ergosterol B, 435,436 Ergosterol Bj, 435,436 Erythronolide B, 84 Ester cleavage, 304, 447 Ester hydrolysis, 262 Esterification, 95, 163, 186, 230, 500 Esters, 444... 

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