Direct total synthesis of vitamins D2 and D3

Lythgoe, B.; Nambudiry, M. E. N.; Tideswell, John

doi:10.1016/s0040-4039(01)83327-x

Cited by 21 publications

(7 citation statements)

References 9 publications

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“…Synthesis of the target vitamins 8 – 13 was achieved by applying Lythgoe’s strategy − based on the Wittig–Horner reaction. A-Ring phosphine oxide 14 (Figure ), described by us previously, was coupled with corresponding Grundmann ketones 15a – 15f , which in turn were obtained from protected hydroxy aldehyde 16 (Scheme 1S, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Biological Activity of 2,22-Dimethylene Analogues of 19-Norcalcitriol and Related Compounds

et al. 2020

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Continuing our search for vitamin D analogues, we explored the modification of the steroidal side chain and inserted a methylene moiety in position C-22 together with either lengthening the side chain or introducing a ring at the terminal end. Our conformational studies confirmed that the presence of a methylene group attached to C-22 restricts the conformational flexibility of the side chain, which can result in changes in biological characteristics of a molecule. All synthesized 1α,25-dihydroxy-2,22-dimethylene-19-norvitamin D3 analogues proved equal to calcitriol in their ability to bind to the vitamin D receptor, and most of them exert significantly higher differentiation and transcriptional activity than calcitriol. The most active compounds were characterized by the presence of an elongated side chain or 26,27-dimethylene bridge. The synthetic strategy was based on the Wittig–Horner coupling of the known A-ring phosphine oxide with the corresponding Grundmann ketones prepared from a 20-epi-Inhoffen-Lythgoe diol derived from vitamin D2.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Biological Activity of 2,22-Dimethylene Analogues of 19-Norcalcitriol and Related Compounds

et al. 2020

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“…for example, vernolepin and vernomenin [65] and in vitamin D 2 and D 3 syntheses. [66] However, we have studied the reaction of iodination followed by ring-closure of unsaturated alcohols and carboxylic acids by this method. For this purpose, the lactonization of 4-pentene-1-carboxylic acid as a model reaction was studied.…”

Section: Resultsmentioning

confidence: 99%

“…[58,59] Examples consist of Coreys prostaglandin synthesis, [60] total synthesis of tumor inhibitors, for example, vernolepin and vernomenin [61] and in vitamin D 2 and D 3 synthesis. [62] In this study, we have also paid attention to the application of this catalytic system for haloetherification and halolactonization reactions.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in Water

et al. 2009

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In this article a new environmentally friendly catalytic method is described for the efficient monoiodination and bromination of arenes and also iodoetherification and iodolactonization of olefins using hydrogen peroxide as the terminal oxidant. The method is based on using sodium iodide or sodium bromide, hydrogen peroxide (35%) and ceriumA C H T U N G T R E N N U N G (III) chloride as an effective catalyst in water at room temperature or under reflux conditions. By this protocol, iodination of anilines proceeded with high regioselectivity at the para position with the formation of small amounts of the ortho isomers. However, bromination of anilines proceeded with absolute regioselectivity to give the para isomers as the sole products in high yields. Iodinations and brominations of m-xylene, toluene, chloro-and bromobenzenes were proceeded with excellent regioselectivity to produce the para isomers as the sole products. Benzene was also halogenated by this catalytic system to give the monohalogenated benzene in good yields. Iodoetherification and iodolactonization of olefins also proceeded easily in high yields at room temperature. However, the bromination of olefins by this protocol failed and the starting materials were detected intact.

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“…101,102) The systems chosen for study were the (arylsulfinyl), (arylsulfonyl), and (diphenylphosphinyl)methylcyclobutenes, dienes generated from them constituting an essential part of the skeleton of the vitamin D series. 103,104) All the reactions were carried out in THF at Ϫ30°C for 10 min using n-butyllithium as base and were found to proceed in moderate to high yields to give the initial products 110a-f together with the double [2,3] sigmatropic rearrangement products 111a and 111b in case of entries 5 and 7, respectively (Table 5, Chart 15). A very attractive feature of this method of diene generation is that alkylation of 109c and 109e, involving essentially the same conditions as above, nBuLi/THF, can be carried out at Ϫ78°C, at which temperature the butene ring remains intact.…”

Section: Novel Reaction Mode and Substituent Effectmentioning

confidence: 99%