98301-34-9Relevant academic research and scientific papers
Stereoselective Introduction of Hydroxy Groups into the Cholesterol Side Chain. Preparation of (24R)- and (24S)-24,25-Dihydroxy- and (25R)- and (25S)-25,26-Dihydroxyvitamin D3 by Asymmetric Synthesis
Koizumi, Naoyuki,Ishiguro, Masaji,Yasuda, Mitsuhiro,Ikekawa, Nobuo
, p. 1401 - 1410 (2007/10/02)
24,25-Epoxy-26-hydroxy-3β-tetrahydropyranyloxycholest-5-enes (7a) and (8a), prepared by asymmetric epoxidation of the allylic alcohol (4), and 24-hydroxy-3β-tetrahydropyranyloxycholesta-5,25-dienes (11) and (12), synthesized by asymmetric reduction of the enone (6), were stereoselectively converted into 25,26-and 24,25-dihydroxycholesterol derivatives, which could be transformed into 25,26- and 24,25-dihydroxyvitamin D3.The highly stereoselective epoxide cleavage of 26-benzoyloxy-24,25-epoxides (7b), (8b), (25), and (26) was found to proceed with retention at C-24.
