The chemistry of metallacyclic alkenylcarbene complexes

Synthesis and selective silylation of ω-hydroxy functionalized (η2-alkenyl)carbene complexes of chromium(0) and tungsten(0) Part 11. The chemistry of metallacyclic alkenylcarbene complexes

“…Starting materials were prepared according to the literature procedures, e.g. (OC) 5 M@C(OMe)R (M ¼ Cr, W; R ¼ Me, Ph) [16], HOCH 2 CH@CHCH 2 NHMe [7] or were used as purchased, without further purification, e.g. HOCH 2 CH@ CHCH 2 OH, SOCl 2 , NH 2 Me, M(CO) 6 (M ¼ Cr, W), MeLi NMR spectroscopy: Bruker ARX 250, DRX 300 and DRX 500 ( 1 H, 13 C); direct single pulse runs, or in the case of the 29 Si and some 13 C NMR spectra by using the refocused INEPT pulse sequence with 1 H decoupling [17], based on 2 J( 29 Si, 1 H) % 7 Hz or n J( 13 C, 1 H) % 3-5 Hz.…”

“…Synthesis of (OC) 5 M@C(NMeCH 2 CH@ CHCH 2 OH)R (1) [7] and (2) -general procedure 1-Methylamino-but-(2Z)-en-4-ol (1.01 g, 10.0 mmol), dissolved in THF (10 ml), was added at once to a solution of (CO) 5 M@C(OMe)R (M ¼ Cr, W; R ¼ Me: 5.2 mmol, Ph: 3.4 mmol) in THF (50 ml). The mixture was stirred at room temperature for 3 h (for 1) or 4 h (for 2).…”

“…4.3. Synthesis of (OC) 4 M@C(g 2 -NMeCH 2 CH@CH CH 2 OH)R (3) [7] and (4) -general procedure A solution of (OC) 5 M@C(NMeCH 2 CH@CHCH 2 -OH)R 1 or 2, respectively (3.0 mmol) in THF (80 ml) was irradiated at )20°C (2) or )30°C (1) for 2-3 h with a Heraeus low-pressure mercury lamp (150 W) in an apparatus described elsewhere [7]. The solvent was removed in vacuo and the resulting residue was chromatographed on silica gel.…”

“…The NMR spectra of complexes 2, 4, of the known [7] chromium analogues 1 and 3, and of silyl derivatives of 3a and 4a are discussed as reflecting minor structural differences. …”

Syntheses, structures and electrochemistry of some 1-(η2-allylamino)-1-ferrocenylcarbene complexes of chromium(0), molybdenum(0) and tungsten(0)

“…doi:10.1016/j.jorganchem.2005. 10.047 established method [20,21]. We also took a closer look at the Z/E ratios of the uncoordinated precursor complexes which are crucial for the yield of the photo-chelation step.…”