A direct, selective, and general method for reductive deamination of primary amines

A Concise Total Synthesis of (R)‐Puraquinonic Acid

“…We initially assigned the stereochemistry of the alkylation sequence by comparing the optical rotation of an alkylation product to literature data. [16] The deamination product proved to be identical to 24 a, which is the major product derived from reduction and alkylation of 4 b with benzyl bromide followed by partial aminal hydrolysis, and was clearly different than 24 b, which is the product derived from an identical sequence on lactam 4 c. This result confirmed that our original assignment of stereochemistry of the alkylation sequence was correct and strongly supports the conclusion that we have prepared (R)-puraquinonic acid. [8] Fortuitously, the stereochemistry of Mannich addition products was assigned unambiguously by X-ray crystallography, and we reasoned that a deamination process would allow direct comparison to products 24 a and 24 b formed from a standard alkylation sequence (Scheme 7).…”

“…a monoalkyl diazene by using hydroxylamine O-sulfonic acid. [16] The deamination product proved to be identical to 24 a, which is the major product derived from reduction and alkylation of 4 b with benzyl bromide followed by partial aminal hydrolysis, and was clearly different than 24 b, which is the product derived from an identical sequence on lactam 4 c. This result confirmed that our original assignment of stereochemistry of the alkylation sequence was correct and strongly supports the conclusion that we have prepared (R)-puraquinonic acid. We presume that the source of discrepancy between our observed rotation and the literature lies in the small absolute value for rotation, which may render the determination of sign within the error limits of standard polarimetry on small samples.…”

Reduction of Saturated Alcohols and Amines to Alkanes

“…Because the lower degree of stabilization of primary radicals retards the fragmentation (process (A) in Scheme 5), the standard procedure was inefficient for O-thiocarbonyl derivatives of primary alcohols, but was rendered acceptable by running the reductive step at 150°C.50 Conversion of methylhederagenin (77) to monoxanthate (78) followed by heating with BU3SnH in p-cymene gave methyl oleanolate (79) in 51 % overall yield.…”

Efficient synthesis of glutaric acid from L-glutamic acid via diazoniation/hydrogenation sequence

“…However, to the best of our knowledge, the transformation of aliphatic amines has been disclosed only rarely in comparison with the numerous reports on aromatic amines. Nickon and Hill (1964) and Doldouras and Kollonitsch (1978) conducted the deamination of aliphatic amines with hydroxylamine-O-sulphonic acid, whilst the preparation of α-hydroxy acids by the diazoniation of natural amino acids was disclosed by Kolitz et al (2009); however, there has been no report on the deamination via diazoniation of aromatic amines. Furthermore, it was reported that, in contrast with aromatic amines, aliphatic primary amines did not react with nitrous acid below a pH value of 3.0 (Kornblum & Iffland, 1949).…”