566-93-8Relevant articles and documents
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Throndsen,H.P. et al.
, p. 2342 - 2346 (1962)
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Electrosynthesis of cholesta-4,6-dien-3-one from cholesterol on a laboratory synthetic scale
Hosokawa, Yu-Ya,Hakamata, Hideki,Murakami, Tomonori,Kusu, Fumiyo
, p. 129 - 132 (2010)
Cholesterol has been shown to be electrochemically oxidized at a carbon electrode to form cholesta-4,6-dien-3-one in acetonitrile [Hosokawa, Y. Y.; Hakamata, H.; Murakami, T.; Aoyagi, S.; Kuroda, M.; Mimaki, Y.; Itoh, A.; Morosawa, S.; Kusu, F. Electrochim. Acta, 2009, 54, 6412-6416]. To further expand on this reaction in the field of organic synthesis, the electrolysis conditions of cholesterol were optimized on a laboratory synthetic scale. Using a flow-through column electrolysis system, cholesta-4,6-dien-3-one was efficiently produced at the applied potential of 1.9 V versus Ag/AgCl with a flow rate of 2.5 mL/min, providing a green tool for the synthesis of cholesta-4,6-dien-3-one.
Platinum-Catalyzed α,β-Desaturation of Cyclic Ketones through Direct Metal–Enolate Formation
Chen, Ming,Dong, Guangbin
supporting information, p. 7956 - 7961 (2021/03/01)
The development of a platinum-catalyzed desaturation of cyclic ketones to their conjugated α,β-unsaturated counterparts is reported in this full article. A unique diene-platinum complex was identified to be an efficient catalyst, which enables direct metal-enolate formation. The reaction operates under mild conditions without using strong bases or acids. Good to excellent yields can be achieved for diverse and complex scaffolds. A wide range of functional groups, including those sensitive to acids, bases/nucleophiles, or palladium species, are tolerated, which represents a distinct feature from other known desaturation methods. Mechanistically, this platinum catalysis exhibits a fast and reversible α-deprotonation followed by a rate-determining β-hydrogen elimination process, which is different from the prior Pd-catalyzed desaturation method. Promising preliminary enantioselective desaturation using a chiral-diene-platinum complex has also been obtained.
P -TsOH-Catalyzed one-pot transformation of di- and trihydroxy steroids towards diverse A/B-ring oxo-functionalization
Sarkar, Antara,Das, Jayanta,Ghosh, Pranab
, p. 9051 - 9060 (2017/08/29)
A solid support-mediated p-TsOH-catalyzed milder transformative protocol was developed to furnish diverse ring-A and/or ring-B oxo-functionalized steroids. To furnish interesting isomers involving the A/B-ring of biomolecules in a one-pot approach, only solid supports (and not solution!) were found to be effective. p-TsOH/SiO2-oxidation of 4β-hydroxycholesterol, the major oxysterol in human circulation, into a mixture of cholest-4-en-3-one, cholest-4-ene-3,6-dione, and 5α-cholestane-3,6-dione was the starting point for the investigations herein. The reaction protocol was optimized in detail, and efforts were carried out toward gaining an understanding of the mechanistic aspects favoring the solid support, and a possible synergetic catalytic system involving p-TsOH and SiO2 was expected to be a key part. Application of the novel methodology to 4β,7α-dihydroxy steroids resulted in the desired diverse ketosteroids through oxidation/oxidative dehydration, which generalized the process as a facile multi-oxo-functionalization steroidal transformation.
2-Iodoxybenzoic acid organosulfonates: Preparation, X-ray structure and reactivity of new, powerful hypervalent iodine(v) oxidants
Yusubov, Mekhman S.,Svitich, Dmitrii Yu.,Yoshimura, Akira,Nemykin, Victor N.,Zhdankin, Viktor V.
supporting information, p. 11269 - 11271 (2013/12/04)
New powerful hypervalent iodine(v) oxidants, tosylate and mesylate derivatives of 2-iodoxybenzoic acid (IBX), were prepared by the reaction of IBX with the corresponding sulfonic acids. Single crystal X-ray crystallography of the diacetate derivative of IBX-tosylate revealed an unusual heptacoordinated iodine geometry without any significant intermolecular secondary interactions.
