Acids, 2-keto-3,4-dihydroxy, lactonization

Irradiation of 5,6jS-dihydroxy-17/i-acetoxy-5/i-androstan-19-oic acid 5,19-lactone (65) afforded 5,6/5-dihydroxy-17 -acetoxy-5a-androstan-19-oic acid 6,19-lactone (66), via a keto-keten intermediate generated by the photo-fission of... [Pg.342]

Dihydroxy esters of the type 5a can easily be lactonized with concomitant elimination of water to give the corresponding a, 3-unsaturated lactones. Therefore, hydroxy keto ester (R)-2c, obtained by recLBADH-catalyzed reduction of Ic, was reduced with NaBH4 prior to acid-catalyzed lactonization for the synthesis of labdanum fragrance compound (R)-16 (Scheme 2.2.7.8) [12]. [Pg.391]

Lactonization, of 2-keto-3,4-dihydroxy acids or esters, II, 83, 87 Lactoprene, IV, 318... [Pg.371]

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