Rearrangement Nametkin

Scheme 7.19). Prototropic shift of the initial adduct to produce ROCHCl2 and, subsequently, the formate ester is a less favourable pathway. Alternatively, the carbon monoxide-separated ion-pair can lose a proton leading to an alkene, or cycloadducts derived from further reaction with the carbene. The formation of rearranged products from the reaction of 1 -hydroxymethyladamantane suggests that a relatively unencumbered carbenium cation can also be generated, which leads to a Nametkin rearrangement of the system [4]. 

The retention of optical activity of camphene rules out methyl migration (Nametkin rearrangement) (71) or a symmetrical intermediate. On the acidic alumina at low contact time the retention of optical activity is high, about 80%. At longer contact time, however, there is essentially complete racemization. Hence, the dehydration mechanism seems to be the same on the acidic and on the base-modified alumina. The acidic alumina, however, causes the readsorption of the dehydration product leading to isomerization and equilibration. 

The rearrangement of camphene hydrochloride is called the Nametkin Rearrangement... 

Nametkin rearrangements. A method of avoiding racemization was to use (+)-3-ent/o-bromocamphor (31), when only the (+)-3-e/isulfonic acid (32) was formed. This problem of racemization has arisen in other situations, for example in syntheses in the alkene series. - ... 

WAGNER-MEERWEIN-NAMETKIN Rearrangement Skeletal rearrangement via carbocations (see 1st edition). 

This reaction is related to the Nametkin Rearrangement, Retropinacol Rearrangement, Tiffeneau Reaction, and Wagner-Meerwein Rearrangement. 

Komppa, G. Nyman, G. A. The cleavage of water from camphenUol, 4-methylcamphenilol and 4-methylbomeol The santene shifting and the Nametkin rearrangement. Ber. 1936,69B, 334-340. 

---