Synthesis of novel prostaglandins containing a boronate in the α chain

Feng, Zixia; Hellberg, Mark R.

doi:10.1016/s0040-4039(00)00973-4

Cited by 13 publications

(8 citation statements)

References 4 publications

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“…B 2 pin 2 is the most effective reagent for the formation of arylboronic esters from aryl halides and for the borylation of hydrocarbons. Exchange of pinacol for catechol at three-coordinate boron has been reported. , Thus, we used a standard exchange process to access this material. Formation of di- tert -butylcatecholate 12 in one pot from BCl 3 and 4- tert -butylcatechol and addition of 2 equiv of pinacol, followed by stirring at room temperature for 1 h, gave complete conversion of 12 to B 2 pin 2 by 1 H NMR spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

A Short Synthesis of Tetraalkoxydiborane(4) Reagents

et al. 2002

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The synthesis of a series of bis(catecholato)diborane(4) compounds, B2(1,2-O2C6H4)2, B2(1,2-O2C6H3Me-4)2, B2(1,2-O2C6H2Me2-3,5)2, B2[1,2-O2C6H3Bu t -4)]2, and B2[1,2-O2C6H2Bu t 2-3,5]2, is reported. The compounds have been synthesized by reaction of 1% sodium/mercury amalgam with the corresponding halocatecholboranes, which are cleanly formed from the reaction of BCl3 or BBr3 and catechol. Combining these two steps in one pot, B2[1,2-O2C6H3Bu t -4)]2 was prepared from BCl3 and 4-tert-butylcatechol, and B2[1,2-O2C6H2Bu t 2-3,5]2 was prepared from 3,5-di-tert-butylcatechol and BBr3 on a multigram scale. Bis(pinacolato)diborane(4) was not formed from reaction of chloropinacolborane and Na/Hg, but it was formed by in situ addition of pinacol to either B2[1,2-O2C6H3Bu t -4)]2 or B2[1,2-O2C6H2Bu t 2-3,5]2. Cyclic voltammetry indicated that the reduction potentials of the chlorocatecholborane reactant and of the bis(catecholato)diborane(4) product are similar. These similar potentials make selective reduction of haloborane difficult and thus far unique to sodium−mercury amalgam.

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Section: Resultsmentioning

confidence: 99%

A Short Synthesis of Tetraalkoxydiborane(4) Reagents

et al. 2002

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“…Then, we prepared pinacol 4-bromo-butylboronate 2 in 85% yield after trans-esterification of 1 in the presence of excess pinacol in THF, as already described (Scheme 1). 18 To find the optimum conditions for the alkylation of 3 by bromide 2, different conditions were tested. The highest yield (83%, after column chromatography) and diastereoselectivity (90/10, determined by 1 H NMR) for alkylated complex 4 were obtained by the addition at -50 °C of 3.0 equiv of tBuOK to a mixture of bromide 2 (1.25 equiv) and Ni II complex 3 dissolved in THF, followed by stirring for 40 min at room temperature (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

“…Satisfactory spectroscopic data ( 1 H and 13 C NMR and MS) have been obtained for all compounds synthesized in this study and previously described in the literature. 16,18,19 (19) Kettner, C.; Mersinger, L.; Knabb, R. J. Biol. Chem.…”

Section: Methodsmentioning

confidence: 99%

Improved and High Yield Synthesis of the Potent Arginase Inhibitor: 2(S)-Amino-6-boronohexanoic Acid

Vadon-Legoff

Dijols

Mansuy

et al. 2005

Org. Process Res. Dev.

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A simple three-step synthesis of the potent arginase inhibitor 2(S)-amino-6-boronohexanoic acid (ABH) has been developed. The key step was alkylation of the NiII complex of the Schiff base derived from glycine and (S)-2-[N‘-(N-benzylprolyl)amino]benzophenone (BPB) with pinacol 4-bromobutylboronate. Acidic hydrolysis afforded ABH in 50% overall yield, high enantiomeric excess, and quantitative recovery of the chiral auxiliary.

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“…All reagents were obtained from commercial sources and used without further purification, unless otherwise noted. N,N-diethyl-3-pentanamine, 1 2-(4bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (Br(CH 2 ) 4 Bpin), 2 Cp*Rh(C 6 Me 6 ), 3 [(COD)IrCl] 2 , 4 O,O'-(S)- (1,1'-dinaphthyl-2,2'-diyl) -N,N'-di-(S,S)-phenylethylphosphoramidite, 5 and Pd(dba) 2 6 were prepared using the reported procedures. Triethylamine, 1-ethylpiperidine, 1butylpiperidine, and N,N-diethyl-3-pentanamine were dried over CaH 2 and vacuum transferred prior to use.…”

Section: S2mentioning

confidence: 99%