77 デオキシアミノ配糖体抗生物質ホーチミシンAの立体選択的合成 : (-)-ホータミンの合成

概要

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The diester 1 was hydrolyzed with pig liver esterase (PLE) to afford a chiral half-ester 2 in 98% yield with 96% optical purity. It should be mentioned here that this chiral half-ester 2 is easily prepared in 100g scale in a usual laboratory. The chiral half-ester 2 is a versatile synthon for various chiral cyclohexane derivatives. First, 2 was efficiently converted to four β-amino acid derivatives (3, 4, 10, 11) under complete stereocontrol. Furthermore, these β-amino acid derivatives are considered to be potential intermediates for various natural products containing β-amino acid moiety. Next, the aminocyclitol moiety of fortimicin A, (-)-fortamine, was synthesized enantioselectively from 2, based on symmetrization-asymmetrization concept. The key features of the present strategy include; (1) transformation of the chiral half-ester 2 to (-)-fortamine was completed in 25 steps and 22% overall yield under strictly stereo- and regiochemical control. (2) the interesting intramolecular carbamation was developed during the synthesis. (3) this strategy is suitable for the preparation of fortamine derivatives at 2 and/or 3 positions which will give us an interesting information about the structure-activity relationships of the 1,4-diaminocyclitol antibiotics.
天然有機化合物討論会の論文
1986-09-09