Absolute Stereochemistry of Atisine and Garrya Alkaloids

Correlations and Absolute Stereochemistry of Atisine and Garrya Alkaloids [Pg.155]

The atisine and Garrya (35,36) alkaloids have been interrelated by converting both atisine (XXX) and veatchine, by a parallel sequence of degradations, to the same A-acetyl ester (XCV) (35, 36). The respective azomethine acetates (LXXXVII, LXXXVIII) derived from atisine (12,16-bond) and veatchine (13,16-bond) were converted to the A-acetyl derivatives (LXXXIX, XC) by reduction, acetylation, and saponification. Oxidation of LXXXIX and CX with permanganate/periodate under controlled conditions gave the respective carboxylic acids (XCIa, [Pg.155]

Reactions of the Imine Group Removal of the Nitrogen from the Diterpbnb Alkaloids [Pg.155]

Recently success in removing the nitrogen from XCVIII has been achieved through a mild reaction with nitrous acid in aqueous dioxane containing sodium acetate (37, 38). The major product is the hemiacetal XCIX (v, ax 3350, 1050 cm i), which was oxidized with bromine water to [Pg.155]

LiAlH4 regenerated the corresponding hemiacetal (XCIX) in good yield but a similar reduction of lactone CV gave a mixture of unchanged lactone, the diol CIV, and the hemiacetal XCIX. [Pg.158]

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