Tamura reagent

Tamura s reagent (2,4,6-Me3C6H2S02NH2) has been used to convert ketones directly to amides. 

Delair and colleagues found that an asymmetric pyrrolidone 344 might serve as a common precursor of (+)-Retronecine 345 and (+)-Amphorogynine A and D (equation 132). The ring expansion was a key and efficient step during the synthetic process and was performed with Tamura s Beckmann reagent. 

Similarly, the application of Tamura s Beckmann rearrangement reagent to ketones 367 and 370 afforded the appropriate lactams 368 and 371 to be cyclized to the indolizidine nucleus 369 and yilP (equations 146 and 147). 

In 1971, Tamura and Kochi described the reaction of aUcyl Grignard reagents with alkenyl bromides in the presence of iron(III) chloride in THF. Only very reactive snbstrates such as vinyl and propenyl bromide were nsed (Scheme 16). Yields of conpling product are moderate to good but, unfortunately, a large excess of alkenyl bromide is required (3 to 9 equivalents). ( )-Bromopropene reacts 15 times faster than the (Z)-isomer. It should be noted that the reaction is stereoselective. 

In 1971, a year before the groups of Corriu and Kumada [5] independently reported the groundbreaking work on the topic of nickel-catalyzed cross-coupling reactions of aryl and vinyl halides with Grignard reagents, Tamura and Kochi described an iron-catalyzed vinylation reaction of Grignard reagents with vinyl halides (Scheme 5.1) [6]. 

Tamura and Kochi studied the cross-coupling reactions of alkyl halides with alkyl Grignard reagents catalyzed by silver compounds first [422, 426, 427]. The coupling of primary alkyl halides with primary Grignard reagents resulted in a mixture... 

Tamura, Y, Minamikawa, I, and Ikeda, M. 1977. O-Mesitylenesulfonylhydroxylamine and related compounds. Powerful aminating reagents. Synthesis 1-17. 

The utility of this reagent has been demonstrated by Tamura et al. in its reaction with the readily enol-izable ketone The ethynylation of the ketone proceeds smoothly with the cerium reagent, as... 

Hydroxylamine-O-sulfonic acid or 0-mesitylenesulfonylhydroxylamine (Tamura s reagent) are effective catalysts for the conversion of ketones directly to lactams. For example, the rearrangement of... 

Tamura, M., Kochi, J. Coupling of Grignard reagents with organic halides. Synthesis 1971, 303-305. 

Fig. 23-17. Comparative rates of decomposition of dialkylmanganese in tetrahydrofuran at 2° (0.048M MnCl2, 0.27M Grignard reagent), the alkyl group being as stated in the diagram. [Reprinted by permission from M. Tamura and J. Kochi, J. Organometallic...

Alkenyl halides couple readily with Grignard reagents in the presence of iron. -E n-Hexylmagnesium bromide allowed to react at 0° with vinyl bromide in tetrahydrofuran in the presence of FeClg 1-octene. Y 83%. F. e. s. M. Tamura and J. Kochi, Am. Soc. 93, 1487 (1971) also coupling with satd. halides in the presence of Ag - and Cu -catalysts s. Synthesis 1971, 303. 

Oishi T, Akita H 0983) Asymmetric reduction by yeasts. Formation of optically active synthons having two chiral centers useful for natural product synthesis. J Synth Org Chem Jpn 41 1031-1043 Okamoto T, Ohno A, Oka S (1977a) Reaction of N-propyl-1,4-dihydro-nicotinamide with ferricyanide ion. J Chem Soc Chem Commun 181-182 Okamoto T, Ohno A, Oka S (1977b) Alkali-metal ion acceleration of the electron-transfer reaction between N-propyl-1,4-dihydronicotinamide and ferricyanide ion. J Chem Soc Chem Commun 784-785 Okamoto T, Ohno A, Oka S (1979) Reduction of transition-metal salts by N-propyl-1,4-dihydronicotinamide. Bull Chem Soc Jpn 52 3745-3746 Ono N, Tamura R, Kaji A (1980) 1-Benzyl-1,4-dihydronicotinamide as a reagent for replacing aliphatic nitro groups by hydrogen An... 

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