Reactions of Sodiurn Borohydride in Acidic Media; IV. Reduction of Diarylmethanols and Triarylmethanols in Trifluoroacetic Acid<sup>1-3</sup>

Gribble, Gordon W.; Leese, Robert M.; Evans, B.

doi:10.1055/s-1977-24308

Cited by 128 publications

(60 citation statements)

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“…In an attempt to increase the yield, this latter reaction with 4 a was repeated several times, where the temperature was varied and the amount of the reductant varied (2 to 5 equivalents of TMSCl/NaI) but without any significant improvement. Moreover different reducing agents were tested: the use of I 2 in H 2 PO 3 or FeCl 3 / polymethylhydrodisiloxane (PHMS) which afforded overall yields of 33% and 38% respectively for BDT, while only traces of BDT were obtained using NaBH 4 in CF 3 CO 2 H . During the set‐up of this reaction it was also found that the treating of an EtOH solution of 4 a with concentrated HCl (Scheme ) afforded the corresponding ethylether 8 a (88%), from which the reaction with NaI/TMSCl gave again BDT in 53% yield.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Benzo[1,2‐b:4,5‐b’]dithiophene and Benzocondensed Thiaheterocycles

2019

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A two‐step synthesis of benzo[1,2‐b:4,5‐b’]dithiophene (BDT) was carried out starting from 3‐thiophene carbaldehyde as the sole thiophene precursor. This method involves the selective lithiation of the 2‐position of 3‐thiophenecarbaldehyde ethylene acetal, followed by the condensation with 3‐thiophenecarbaldehyde and subsequent dehydrative cycloaromatization of the dithienylmethanol intermediate to give BDT. This synthetic pathway was extended to other thiophene benzocondensed heterocycles.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Benzo[1,2‐b:4,5‐b’]dithiophene and Benzocondensed Thiaheterocycles

2019

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“…This coupling produced carbinol 11 in a 71% yield and allowed for the generation of a protected-sobetirome intermediate containing a site (carbinol) for radiolabeling with NaB 3 H 4 . After optimization of a procedure developed by Gribble and colleagues 14 for reducing carbinols to diarylmethanes using TFA and NaBH 4 for 11 , 3 H-sobetirome 12 was prepared from 11 with NaB 3 H 4 and TFA in DCM. Although the tritium-labeling/deprotection procedure proceeded in only 11% yield from 11 , the fast reaction time (10 minutes) and high specific activity (6.90 mBq) obtained made the labeling procedure a satisfactory final step in the synthesis of 3 H-sobetirome.…”

Section: Resultsmentioning

confidence: 99%

New synthetic routes to thyroid hormone analogs: d6-sobetirome, 3H-sobetirome, and the antagonist NH-3

Placzek

Scanlan

2015

Tetrahedron

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New synthetic routes for the preparation of isotopically labeled versions of thyroid hormone agonist sobetirome were developed using Knochel’s iodine-magnesium exchange. A more efficient synthesis of the thyroid hormone antagonist NH-3 was developed from a common intermediate in the sobetirome route. Using the new synthetic routes, d6- and 3H-sobetirome were prepared for their use in studying biodistribution and the cellular uptake of sobetirome. The new route to NH-3 allows for a more rapid and efficient synthesis and provides access to an advanced intermediate to facilitate antagonist analog production in the final bond-forming synthetic step.

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“…Addition of the bicyclic compound to a solution of KO t -Bu in t -BuOH provided enone 97 in excellent yield. Subsequent reductive deoxygenation using the Gribble protocol [45] provided tricyclic alkene 96 in 27% yield. Notably, the two routes provided efficient access to the tricyclic olefin core in 7 or 8 steps without the use of protecting groups.…”

Section: Synthetic Studies Toward the Presilphiperfolanol Natural mentioning

confidence: 99%

Biosynthesis and Chemical Synthesis of Presilphiperfolanol Natural Products

Hong

Stoltz

2014

Angew Chem Int Ed

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Presilphiperfolanols constitute a family of biosynthetically important sesquiterpenes that can rearrange to diverse sesquiterpenoid skeletons. While the origin of these natural products can be traced to simple linear terpene precursors, the details of the enzymatic cyclization mechanism that form the stereochemically dense tricyclic skeleton have required extensive biochemical, computational, and synthetic investigation. Parallel efforts to prepare the unique and intriguing structures of these compounds by total synthesis have also inspired novel strategies, resulting in two synthetic approaches and two completed syntheses. While the biosynthesis and chemical synthesis studies performed to date have provided much insight into the role and properties of these molecules, new questions regarding the biosynthesis of newer members of the family and subtle details of the cyclization mechanism have yet to be explored.

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Reactions of Sodiurn Borohydride in Acidic Media; IV. Reduction of Diarylmethanols and Triarylmethanols in Trifluoroacetic Acid^1-3

Cited by 128 publications

References 0 publications

Synthesis of Benzo[1,2‐b:4,5‐b’]dithiophene and Benzocondensed Thiaheterocycles

Synthesis of Benzo[1,2‐b:4,5‐b’]dithiophene and Benzocondensed Thiaheterocycles

New synthetic routes to thyroid hormone analogs: d6-sobetirome, 3H-sobetirome, and the antagonist NH-3

Biosynthesis and Chemical Synthesis of Presilphiperfolanol Natural Products

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Reactions of Sodiurn Borohydride in Acidic Media; IV. Reduction of Diarylmethanols and Triarylmethanols in Trifluoroacetic Acid1-3

Cited by 128 publications

References 0 publications

Synthesis of Benzo[1,2‐b:4,5‐b’]dithiophene and Benzocondensed Thiaheterocycles

Synthesis of Benzo[1,2‐b:4,5‐b’]dithiophene and Benzocondensed Thiaheterocycles

New synthetic routes to thyroid hormone analogs: d6-sobetirome, 3H-sobetirome, and the antagonist NH-3

Biosynthesis and Chemical Synthesis of Presilphiperfolanol Natural Products

Contact Info

Product

Resources

About

Reactions of Sodiurn Borohydride in Acidic Media; IV. Reduction of Diarylmethanols and Triarylmethanols in Trifluoroacetic Acid^1-3