A-Dimethyl- 9- methylsulfonyl hydroxylamine

Handling, Storage, and Precautions reagents for electrophilic aminations with f (f tdimethyl(dialkyl) functionality like (1) are much more stable than their NH2 analogs. Thus the pure compound (1) can be stored at —30°C for at least 1 year. Impure (1) (and related compounds), however, may decompose at rt, as also reported for fV,yV-diethyl-0-(mesitylsulfonyl)hydroxylamine.  

As can be seen from the structures shown, A,jV-dimethyl-0-(methylsulfonyl)hydroxylainine (1) aminates alkyl Grignard compounds (to give 3) and aryl Grignard compounds (to give 4) with moderate yields. The same is true for benzylic anion type carbon atoms (5-9). Compounds (10) and (11) are formed from the corresponding malonates, while (12)-(16) are derived from (es-ter)enolates, although with aryl-stabilized anionic carbon atoms. Metalated cyanides lead to (17)-(19). 

Related amination reactions of organometallic compounds RM have been performed with )V,)V dimethyl-0-(mesityl-sulfonyl)hydroxylamine (20), )V,)V-dimethyl-0-(phenylsul-fonyl)hydroxylamine (21), and )V,)V-dimethyl-O-(j0-tolylsul-fonyl)hydroxylamine (22). Stmctures (23)-(26) provide exanples of A(jV-dimethylamines formed by reactions of RM with the mesitylsulfonyl species (20).  

Disadvantages. Normal enolates are not animated by (1), (20), (21), or (22), probably because of a )8-eliinination of MeSOsH initiated by deprotonation at one of the fV methyl groups. a-Lithiated sulfones like (30) are aminated to give (31) (eq 2) however, the reaction does not stop there. Rather, the a-aminosulfone (31) leads with unreacted (30) to the 8-aminosulfone (32) (eq 3). Without the phenyl substituent at the anionic carhon atom, only the cuprate (33) gives (34) (eq 4).  

The corresponding Li confound deprotonates (1) (or 20-22). With the dibenzylamine reagent (35), amination of RLi is not observed because of the comparatively fast /3-elimination to give (36) due to the rather acidic benzylic hydrogen atoms (eq 5).  

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