A.M.Z. Slawin

Probing the Efficiency of N-Heterocyclic Carbene Promoted O- to C-Carboxyl Transfer of Oxazolyl Carbonates

Screening of a range of azolium salts, bases and solvents for reactivity indicates that triazolinylidenes, generated in situ with KHMDS in THF, promote the Steglich rearrangement of oxazolyl carbonates with high catalytic efficiency (typical reaction time 5 min at <1.5 mol % NHC). This protocol shows wide substrate applicability, even allowing the efficient generation of vicinal quaternary centers. An improved experimental procedure is also described that allows a simplified one-pot reaction protocol to be employed with similarly high catalytic efficiency.

8-Bromo-naphthalen-1-amine.

The title compound, C10H8BrN, was obtained by slow addition of sodium azide to 8-bromo-1-naphthoic acid, followed by addition of aqueous ammonia. The crude product was crystallized from petroleum ether to give pink crystals. Compared to other 1,8-disubstituted naphthalene compounds, this compound exhibits less strain between the 1 and 8 substituents. Additionally, the NH protons form both intra- and intermolecular hydrogen bonds. The naphthalene units are arranged in a herring-bone stacking motif.

5-Benzyl-idene-2,3-diphenyl-1,2-selenaphosphole-2-selenide.

The title compound, C(23)H(19)PSe(2), has a central five-membered twist C(3)PSe ring conformation. One phenyl ring substituent, attached to an sp(2) carbon, is approximately coplanar with the C(3)PSe ring whilst the other organic substituents, attached to an sp(3)-carbon and a P(V) atom, lie on the same side of the ring.

1,5,6-Triphenyl-8-oxa-7-selena-6-phos­phabicyclo­[3.2.1]octane-6-selone

The structure of the title compound, C23H21OPSe2, consists of fused puckered five- and six-membered rings, PSeC2O and C5O, respectively, with a C2O bridgehead. The C5O ring adopts a chair conformation, whilst the C2PSeO ring has an envelope conformation.

(Disulfur dinitrido)triphenyl­anti­mony(V)

The title compound, [Sb(C6H5)3(N2S2)], contains a molecular entity that is very similar to that of the known polymorph of Sb(S2N2)Ph3 [Kunkel et al. (1997 ▶). Z. Naturforsch. Teil B, 52, 193–198], differing only in the orientation of the phenyl rings. The bond order in the SNSN unit is S—N=S=N, consisting of one long S—N bond, an intermediate length N=S bond and a short S=N bond.

2-(4-Fluoro-phen-yl)-3-methyl-1H-indole.

The indole N—H hydrogen in the title compound, C15H12FN, does not display classical hydrogen bonding. Rather it forms an interaction with the π system of an adjacent indole, resulting in weakly interacting chains along the [001] direction.

trans-Dibromidobis(triphenyl­phosphane)platinum(II) chloro­form monosolvate

Both the platininum complex and the solvent molecule of the title compound, [PtBr2(C18H15P)2]·CHCl3, are located on a twofold rotation axis. The CH unit and the Cl atoms of the CHCl3 molecule are disordered over two equally occupied positions. The complex shows a trans square-planar geometry about the Pt atom.

Tris(ethyl­enediamine)zinc(II) hexa­fluorido­silicate

The title compound, [Zn(C2H8N2)3](SiF6), was synthesized ionothermally using choline chloride–imidazolidone as solvent and template provider. In the crystal structure, the anions and cations are located on special positions of site symmetry 3.2 and show a typical octahedral geometry. The ZnII ion is coordinated by six N atoms from three ethylenediamine molecules. The crystal structure displays weak hydrogen bonding between [SiF6]2− anions and the ethylenediamine NH hydrogen atoms.

cis-Dichloridobis(triisopropoxy-phosphine)-platinum(II).

The title compound, [PtCl2(C9H21O3P)2], was obtained from a solution of PtCl2(COD) (COD = 1,5-cyclooctadiene) and triisopropylphosphite in dichloromethane. The complex features a Pt(II) atom coordinated by two Cl and two P atoms, yielding a slightly distorted cis square-planar geometry.

Bis(furan-2-ylcarbon­yl) diselenide

The title molecule, C10H6O4Se2, lies on a twofold rotation axis. The Se—Se bond length of 2.305 (3) Å is similar to that in diphenyl diselenide [2.3066 (7) and 2.3073 (10) Å for the P and M isomers, respectively] and longer than that in 1,8-diselenonaphthalene [2.0879 (8) Å]. The molecule adopts a gauche conformation with respect to the C=O groups.