Stabilization of R-P(H)A species (A = OH, OR, S, NH2, NHR, NR2, Cl, Br, I) by complexation with chromium and tungsten pentacarbonyls

Linear and Branched Phospha[n]triangulanes

“…The structure of the major anti isomer 16 b, separated by column chromatography, was ascertained by an X-ray crystal structure determination ( Figure 2). The presence of the double bond (1.289(14) ) is also evident from the 1 H NMR resonances at d = 5.36 ( 4 J-(H,H) = 2.4 Hz) and 5.39 ( 4 J(H,H) = 1.8 Hz) and the 13 C NMR resonances at d = 101.6 (H 2 C=) and 133.7 (=C). Reaction of the remaining double bond in anti-16 b with an excess of 8 (55 8C, CuCl, 3 h) resulted in the smooth formation of the novel linear diphospha [4]triangulane complex 17 in 78 % yield in a 10:7 ratio of the anti,anti and anti,syn isomers (Scheme 2).…”

“…Spirocyclopropanated methylenecyclopropanes, that is, terminal alkenes: Reaction of Ph-P=W(CO) 5 , generated in situ by the CuCl-catalyzed cycloreversion [12] of 7-phosphanorbornadiene complex 8, [9,13] with methylenespiropentane (9) in toluene at 55 8C (1 h) gave in 78 % yield only the crystalline terminal phospha [3]triangulane complex 12 (Scheme 1) in a 5:4 ratio of the anti (a) and syn isomer (b). Figure 1 shows the X-ray crystal structure for the less congested anti isomer 12 a that has the P-W(CO) 5 group anti to the terminal cyclopropane ring.…”

“…Hydrogen atoms are omitted for clarity. Selected bond lengths [ ] and angles [8]; the values for the second molecule are in square brackets 16 b: C4ÀC5 1.422 (12) [1.423(12)], C4ÀC7 1.500 (13) [1.503(13)], C5ÀC6 1.289(14) [1.289(14], C5ÀC7 1.456(14) [1.475(15)]; C1-P1-C2 48. 4(4) [48.6(4)], C3-C1-C4 60.3 (5) [60.…”

“…[11] The NMR data of the two products are very similar. Characteristic are the 31 P and two 13 C chemical shifts for the ring C-P-C unit of 19 at d 31 P 34.4 ( 1 J(P,W) 238.4 Hz), d 13 C 34.9 ( 1 J(P,C) 39.7 Hz), and 142.5 ppm ( 1 J(P,C) 31.2 Hz) [11] and those for 24 at d 31 P 34.6 ( 1 J(P,W) 234.7 Hz), d 13 C 33.1 ( 1 J(P,C) 40.2 Hz), and 140.3 ppm ( 1 J(P,C) 29.7 Hz). These alkenes, 18 and 22, but also 10 and 25, differ from the others in the fact that they react at room temperature within 18-20 h with the phosphinidene precursor 8 instead of the 55-60 8C, [12] which is usually needed for the CuCl-catalyzed cycloadditions.…”

“…CuCl (99 % purity) was purchased from Acros and stored under nitrogen before use. (5,6-Dimethyl-2,3-bis(methoxycarbonyl)-7-phenyl-7-phosphanorbornadiene) pentacarbonyltungsten (8), [9,13] methylenespiropentane (9), [28] 1-methylenedispiro-[2.0.2.1]heptane (10), [29] 7-methylenedispiro[2.0.2.1]heptane (11), [29,30] 1,4-bismethylenespiropentane (15), [31] perspirocyclopropanated bicyclopropylidene 18, [3] cyclopropylidenespiropentane (20), [32] 7-cyclopropylidenedispiro[2.0.2.1]heptane (22), [30] and ethenylbicyclopropylidene (25) [33] were prepared according to literature procedures.…”