Et3n.2Hf, a new convenient reagent for nucleophilic fluorine displacement reactions

Giudicelli, Marie-Béatrice; Picq, D.; Veyron, B.

doi:10.1016/s0040-4039(00)97108-9

Cited by 62 publications

(33 citation statements)

References 16 publications

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“…C(17)-Hydroxyl-directed epoxidation of the C(18)–C(19) olefin with m -CPBA12c gave a single epoxide diastereomer in 54% yield. Finally, global desilylation of the penultimate intermediate with Et 3 N-buffered Et 3 N-3HF46 provided synthetic (+)-tedanolide. The spectroscopic data ( 1 H NMR, 13 C NMR, IR, optical rotation, HRMS) from our synthetic tedanolide were in excellent agreement with data obtained for an authentic sample,1 as well as with data reported by Kalesse9a,b and Smith10a for synthetic tedanolide.…”

Section: Resultsmentioning

confidence: 99%

Total Syntheses of (+)-Tedanolide and (+)-13-Deoxytedanolide

et al. 2008

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Convergent total syntheses of the potent cytotoxins (+)-tedanolide (1) and (+)-13-deoxytedanolide (2) are described. The carbon framework of these compounds was assembled via a stereoselective aldol reaction that unifies the C(1)-C(12) ketone fragment 5 with a C(13)-C(23) aldehyde fragment 6 (for 13-deoxytedanolide) or 52 (for tedanolide). Multiple obstacles were encountered en route to (+)-1 and (+)-2 that required very careful selection and orchestration of the stereochemistry and functionality of key intermediates. Chief among these issues was the remarkable stability and lack of reactivity of hemiketals 33b and 34 that prevented the tedanolide synthesis from being completed from aldol 4. Key to the successful completion of the tedanolide synthesis was the observation that the 13-deoxy hemiketal 36 could be oxidized to C(11,15)-diketone 38 en route to 13-deoxytedanolide. This led to the decision to pursue the tedanolide synthesis via C(15)-(S)-epimers, since this stereochemical change would destabilize the hemiketal that plagued the attempted synthesis of tedanolide via C(15)-(R) intermediates. However, use of C(15)-(S) configured intermediates required that the side chain epoxide be introduced very late in the synthesis, owing to the ease with which the C(15)-(S)-OH cyclized onto the epoxide of intermediate 50.

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Section: Resultsmentioning

confidence: 99%

Total Syntheses of (+)-Tedanolide and (+)-13-Deoxytedanolide

et al. 2008

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“…Tetrabutylammonium hydrogen fluoride (Bu4N+HF2; TBA ·HF2 ) is prepared by exchange of a counter anion of Bu4N+HS03 with KHC0 3 and then with KHF 2 • Like TBAF, TBA · HF2 fluorinates alkyl halides and sulfonates in a 1: 1 mixture of THF and HMPA at 95 °C, a temperature slightly higher than the reaction temperature of TBAF, to give fluorine-substituted products with much less 2.2 Nucleophilic Fluorinating Reagents 53 olefin formation [175,176]. Nucleophilic fluorination of p-chloronitrobenzene also takes place, but a longer reaction time is necessary.…”

Section: Tfoi)~jomentioning

confidence: 99%

Organofluorine Compounds

Hiyama¹

2000

972

318

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“…Fortunately, Et 3 N·3HF [144], a nearly neutral fluoride source, was found to be effective for desilylation in the model study. When mixed with Et 3 N, Et 3 N·3HF forms the most nucleophilic fluoride species, Et 3 N·2HF [145]. Then, the in situ generated Et 3 N·2HF was used for desilylation of 272.…”

Section: Total Synthesis Of Formamicinmentioning

confidence: 99%

Structures and Total Syntheses of the Plecomacrolides

Dai

Guan²,

Jin

2005

CMC

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The plecomacrolides are a large family of natural products typically featured with a 16- or 18-membered macrolactone possessing two conjugated diene units and a hemiacetal side chain. The macrocycle skeleton is connected with the side chain through a three-carbon linker, forming a biologically important intramolecular hydrogen bonding network among the lactone/linker/hemiacetal structural motif. Many members of the plecomacrolides act as selective inhibitors of vacuolar H+-ATPases (V-ATPases) and they are considered to have the potential for treatment of postmenopausal osteoporosis. Significant progress has been achieved in recent years in the area of plecomacrolide total synthesis. These include the total synthesis of bafilomycin A1 by Evans, Toshima, Hanessian, and Roush, of bafilomycin V1 by Marshall, of hygrolidin by Hashimoto and Yonemitsu, of concanamycin F by Paterson and Toshima, and of formamicin by Roush. The synthetic strategies and key transformations used in the total synthesis are discussed.

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Et3n.2Hf, a new convenient reagent for nucleophilic fluorine displacement reactions

Cited by 62 publications

References 16 publications

Total Syntheses of (+)-Tedanolide and (+)-13-Deoxytedanolide

Total Syntheses of (+)-Tedanolide and (+)-13-Deoxytedanolide

Organofluorine Compounds

Structures and Total Syntheses of the Plecomacrolides

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