- Synthesis of 6-Deoxohomodolichosterone, a New Plant-growth-promoting Steroid
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6-Deoxohomodolichosterone (1), a new member of the brassinosteroid family, was synthesized in twelve steps from stigmasterol (4).Birch reduction of the dienone (5) gave directly 5α-stigmast-22-en-3β-ol (6), the mesylate of which was treated with lithium bromide in refluxing dimethylformamide.Selective oxidation of the 2-ene function of the resulting 2,22-diene (7), followed by acetonide formation, provided the acetonide 22-alkene (8).Epoxide-ring opening of the (22R,23R)-epoxide (9), derived from (8), with phenylselenolate anion, treatment with 30percent hydrogen peroxide, and epoxidation with peracid afforded the 22-hydroxy-23,24-epoxide (15).Ready cleavage of the epoxide ring of compound (15) with aluminium isopropoxide and deprotection yielded 6-deoxohomodolichosterone (1).
- Takatsuto, Suguru,Ikekawa, Nobuo
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p. 2269 - 2272
(2007/10/02)
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