Katsumi Kakinuma

An expeditious chemo-enzymatic route from glucose to catechol by the use of 2-deoxy-scyllo-inosose synthase

Abstract A potential two-step process to catechol from d -glucose comprising one-pot incubation of d -glucose with recombinant 2-deoxy- scyllo -inosose synthase (BtrC) and hexokinase, together with chemical reductive dehydration of the resulting 2-deoxy- scyllo -inosose with HI, was developed.

Amino acid starter unit in the biosynthesis of macrolactam polyketide antitumor antibiotic vicenistatin

Abstract Biosynthetic studies on the starter unit of antitumor antibiotic vicenistatin were undertaken by feeding experiments with (2 S ,3 R )- and (2 S ,3 S )-3-[ 2 H 3 ]methylaspartate, and 3-amino-2-[ 2 H 3 ]methylpropionate. The starter unit of the macrolactam part of vicenistatin was found to be derived from (2 S ,3 S )-3-methylaspartate, but not from the (2 S ,3 R )-isomer. The present as well as the previous results suggest that the starter is formed from l -glutamate through structural rearrangement catalyzed by glutamate mutase to (2 S ,3 S )-3-methylaspartate, which in turn is loaded to polyketide synthase. Additional epimerization and decarboxylation may take place in the process either of activation or condensation to give the final C-18 stereochemistry.

Biosynthetic Pathway of Macrolactam Polyketide Glycoside Antitumor Antibiotic Vicenistatins

The biosynthetic studies of antitumor antibiotic vicenistatin and vicenistatin M were undertaken by feeding experiments with [1-13C]- and [1,2-13C2]acetate, [1-13C]propionate, dl-[2,3,3-2H3]glutamate, d-[6,6-2H2]glucose, l-[15N]glutamate, and l-[CH3–13C]methionine. The elongating units of the macrolactam aglycon were derived from acetate and propionate in a standard manner, whereas the starter unit was not derived from fatty acid, but rather originated from 3-amino-2-methylpropionate or its equivalent, probably formed by the reactions of glutamate mutase and decarboxylase. The sugar units appeared to be biosynthesized through diversed modification of functional groups of a common intermediate.

Versatile route to 2,6-dideoxyamino sugars from non-sugar materials: Syntheses of vicenisamine and kedarosamine

A new strategy for the synthesis of 2,6-dideoxyamino sugars from non-sugar starting materials has been developed. The key reaction in this strategy is the acid-catalyzed intramolecular cyclization, by which a nitrogen functional group is introduced with simultaneous control of vicinal chiral centers. The synthesis of two kinds of 2,6-dideoxyamino sugars, D-vicenisamine and L-kedarosamine, by this strategy is described.

Practical enantioselective synthesis of fully deuterated (R)-mevalonolactone

Abstract Practical enantioselective synthetic method of fully deuterated ( R )-mevalonolactone has been developed based upon Sharpless asymmetric epoxidation. ( R )-Mevalonolactone- d 9 1 was prepared on multi-gram scale in seven steps in 17% overall yield.

Enantioselective total synthesis of vicenistatin, a novel 20-membered macrocyclic lactam antitumor antibiotic

Enantioselective total synthesis of an antitumor antibiotic, vicenistatin, featuring a 20-membered macrocyclic lactam glycoside with the amino sugar vicenisamine, has been achieved. Key reactions in the synthesis of macrolactam aglycone involved Suzuki cross-coupling and Evans asymmetric aldol reaction. Penultimate glycosidation of the O-TMS-aglycone with appropriately protected 1-O-acetyl amino sugar and final deprotection allowed accomplishment of the total synthesis.