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Synthesis and molecular structure of a novel barium arylspiroboronate ester

100%

Halcovitch N. , Geier M. , Vogels C. , Decken A. , Westcott S.

Open Chemistry

2011

tom 9

nr 3

386-390

The compound barium bis{bis-(4,6-di-tert-butyl[1,2-benzenediolato(2-)-O,O′]borate)} has been prepared by the addition of 3,5-di-tert-butylcatechol to a solution of boric acid and Ba(OH)2 and characterized by a single crystal X-ray diffraction study. The title compound crystallized in the triclinic space group P-1, with cell parameters a = 13.280(2) Å, b = 15.755(3) Å, and c = 16.980(3) Å, α = 71.691(2)o, β = 79.528(3)o, γ = 80.741(3)o, Z = 1, and V = 3296.1(10) Å3. The structure was solved by direct methods and refined to a final R = 0.0459 for 14370 reflections with I > 2σ(I). One of the arylspiroboronate ester counterions is bound to the barium atom in a rare example of the η1 bonding mode via a single oxygen of one of the catecholato groups. The coordination sphere around the barium is complemented by four molecules of water, one molecule of acetone and two bridging water molecules, connecting to an adjacent barium atom.

PXPd-catalyzed borylation of aniline derivatives

86%

Wheaton S. , Humanayun Kabir S. , Zhang H. , Vogels C. , Decken A. , Westcott S.

Open Chemistry

2010

tom 8

nr 4

725-731

Addition of pinacolborane (HBO2C2Me4) to 2-iodoaniline can be catalyzed using a number of palladium complexes, including [(t-Bu)2PCl]2PdCl2 (PXPd), to give the corresponding boronate ester 2-H2NC6H4(BO2C2Me4) in excellent yields. The PXPd system could also be used in the catalyzed borylation of substituted anilines to give the corresponding aminoboronate esters in moderate to high yields. [...]

Ugi products containing boronate esters

72%

Appoh F. , Manning M. , Gullon T. , Hansen M. , Bevans E. , Hogan K. , Turner C. , Vogels C. , Decken A. , Westcott S.

Open Chemistry

2008

tom 6

nr 3

359-364

The Ugi reaction with formylphenylboronic acid derivatives as the carbonyl component proceeds to give the corresponding boron-containing dipeptide derivatives (Ugi products) in good yields. [...]

Synthesis, characterization and antifungal testing of 3,4-dihydropyrimidin-2(1H)-(thio)ones containing boronic acids and boronate esters

72%

Duguay D. , Zamora M. , Blacquiere J. , Appoh F. , Vogels C. , Wheaton S. , Baerlocher F. , Decken A. , Westcott S.

Open Chemistry

2008

tom 6

nr 4

562-568

The addition of formylphenylboronic acid derivatives to thiourea and ethyl acetoacetate proceeds in the presence of an additional Lewis acid catalyst to give the corresponding 3,4-dihydropyrimidin-2(1H)-(thio)ones (Biginelli products) in moderate yield. Compounds were tested for antifungal activity against pure cultures of Aspergillus niger, Aspergillus flavus, Candida albicans and Saccharomyces cerevisiae but, unfortunately, none showed any appreciable activity. [...]

Addition of boranes to (E)-(η5-C5H5)2Zr(CH=CHPh)Cl

58%

Ferland P. , Prosser K. , Bourque J. , Edwards I. , Hamilton N. , Joyce L. , Finniss M. , Yorke S. , Vogels C. , Fontaine F.-G. , Decken A. , Westcott S.

Open Chemistry

2013

tom 11

nr 5

811-816

In this study, the addition of boranes to (E)-(η5-C5H5)2Zr(CH=CHPh)Cl (3) has been examined in order to investigate the regioselectivity of these ‘hydroboration’ reactions. We have found that these additions proceed with remarkable selectivity to give exclusive formation of a saturated organic molecule where one carbon atom has both the boron and the zirconium fragments. These reactions do not proceed via a conventional hydroboration reaction, but instead go through an initial transmetalation step to generate (E)-(η5-C5H5)2Zr(H)Cl (1) and the corresponding alkenyl boron intermediate, whereupon subsequent hydrozirconation of this latter species gives the geminal products. An x-ray diffraction study has been conducted on gem-(η5-C5H5)2Zr(CH(Bpin)CH2Ph)Cl (pin = 1, 2-O2C2Me4) (2). Crystals of 2 were orthorhombic with a = 18.545(3) Å, b = 15.713(3) Å, c = 16.157(3) Å in the space group Pccn. An x-ray diffraction study has also been conducted on the trinuclear zirconium oxide species (η5-C5H5)2ZrO2[ZrCl(η5-C5H5)2]2(4). Crystals of 4 were orthorhombic with a = 13.6000(8) Å, b = 14.2252(8) Å, c = 17.6500(10) Å in the space group P2(1)2(1)2(1). [...]