Die obergangsmetall-funktionalisierten Thiaphospharsirane (qsAryl (2c) sind durch Reaktion von (qs-CSHsXCO)(PPh3)FeAs=P-Aryl (la) bzw. (q5-CSMeSXCOkFe-E1=E2-Aryl (lb: E' = As, E2 = P lc: E l = P, E2 = As) mit einem Kquivalent Schwefel zugiinglich. Die Umsetzung von 2c mit weiterem Schwefel fiihrt zum Thiaphospharsiran-P-suEd (qS-C5Mes)(COkFe -f'( = S) -S -i s -Arylt(6). Die Heferocyclen Aryl -As -SAs-Aryl(l3) und Aryl-As-CH2-As-Aryl (15) entstehen aus dem Diarsen Aryl -As = As -Aryl (12) The transition-metal-functionalized thiaphospharsiranes (q5-CSHsXCO PPhJFe -A m -Aryl (2ak (q5-CSMes)(COhAs-Aryl(2c) are obtained from the reaction of (qS-CJHsXCO)-(PPh3)Fe -As = P -Aryl(1 a) and (qS-CSMe&C0)2Fe -E' = E2 -Aryl (lb: E' = As; E2 = P; lc. E' = P, E2 = As) with an equivalent amount of sulfur. Further treatment of 2c with sulfur leads to the thiaphospharsirane P-sulfide (q5-CSMe$(CO~F;-$( = S)-S -ks -Aryl, (6). The h+procycles Aryl -As -S -AsAryl(l3) and Aryl-As-CH2-As-Aryl (15) are generated from the diarsene Aryl-As=As-Aryl(32) and sulfur or diazomethane, respectively. Structure elucidation of 2a--$ 6,13, and 15 is based on spectroscopy (IR, 'H, I3C, "P NMR and MS).Y Fe -As + S --Aryl (2 b), and (qS-CdMes)(COkFe -P -SNunmehr stand die chemische Reaktivitat solcher Systeme im Mittelpunkt des Interesses. Erste orientierende Untersuchungen haben gezeigt, daD Arsaphosphenyl-Komplexe ihrerseits als Liganden in stabilen Pentacarbonylchrom-Komplexen f~n g i e r e n~,~) . Sie entstehen unter anderem durch Umsetzung von Disilylarsenido-Komplexen mit Organodichlorphosphanen') bzw. Disilylphosphido-Komplexen mit Organodichlorarsanen ' ).Aryl-E l CI 2 E1 = As; E2 = P E' = P; E2 = AS Alternativ ist ein Arsaphosphenyl-Komplex des Chroms durch die Umsetzung von C5(CH3)5As = P -Aryl mit (CH,-CN)$3(CO), zuganglich ').
I I
40°C. Slow warm-up to room temperature, column chromatographic work-up (silica gel flash chromatography, elution with a 10 : 1 : 1 mixture of dichloromethane, petroleum ether (30-50°C) and diethyl ether), and Kugelrohr distillation (bath temperature 45 "C at 0.1 torr) afforded the a-methylene-p-lactones 9a-c in 27, 48 and 40% yields, respectively, as pale yellow liquids with a pungent odor. Satisfactory elemental composition (9a exact mass by mass spectrometry and 9b, c combustion analyses) and appropriate spectral data (IR; 'H-and I3C-NMR, MS) substantiate the proposed 3-methyleneoxetan-2-one structures for 9. Significant in this context is that the position of the IR absorption of the exo -C=C-bond in 8 and 9 remained essentially constant at V = 1700-1710 cm-I, while the car-bony1 stretching frequency underwent the expected hypsochromic shift from V = 1790-1795 cm-' in 8 to i;= 1820-1825 cm-' in 9.As anticipated, preliminary results of reactions with 9 reveal that the a-methylene-f-lactones are highly reactive. For example, 9a reacts as dienophile nearly quantitatively with cyclopentadiene, yielding a diastereomeric mixture of [4 + 2]-cycloadducts. At elevated temperatures (ca. 60°C), this highly activated heterocyclic ring system readily polymerizes. The chemistry of these potentially useful building blocks should be of general interest. In view of the high genotoxicity of the analogous a-methylene-y-butyrolactones, which are naturally occurring biologically active compounds,(h1 the potential carcinogenic behavior of this novel class of heterocyclics should be checked.
The dichlorophosphido complexes (η5-C5Me5)(CO)2M–PCl2 (2a: M = Fe; 2 c: M = Ru) react with two equivalents of Ph2C=NSiMe3 to yield the first η1-2,4-diaza-3-phosphapenta-1,4-dien-3-yl complexes (4a,c). Intermediates (η5-C5Me5)(CO)2M–P(Cl)(N=CPh2) (3a,c) are detected by 31P{1H} NMR spectroscopy, the preparation of pure 3a, however, failed. The products 4a, c have been characterized by elemental analysis as well as spectroscopic data (IR, 1H, 13C, 31P NMR, MS). The molecular structure of 4a has been elucidated by single X-ray analysis.
Cycloaddukten. Bei hoherer Temperatur (ca. 60°C) polymerisieren die a-Methylen-p-lactone 9 . Wegen der hohen Gentoxizitat der analogen a-Methylen-y-butyrolactone, die Bestandteile zahlreicher Naturstoffe mit sehr unterschiedlichen biologischen Wirkungen sindI6l, sollten die cancerogenen Eigenschaften dieser neuen Heterocyclenklasse gepriift werden.
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