Optically Active Isoprene(tricarbonyl)iron(0) and Methyltrimethylenemethane(tricarbonyl)iron(0)

Abstract

planar conformation required for oxidation is hindered by non-bonding interactions between the propyl groups and the hydrogen atoms in the 2,7,12,17-positions. The favored hydrogenation of 6 with formation of 5 instead of the expected 7 is probably due to hitherto unexplained kinetic factors, since it is almost certain from the acid-catalyzed tautomerization of 5 to 7 that 7 is the thermodynamically more stable tautomer. , 0. Ermer, ibid. 99 (1987) 909 and 26 (1987) 928. Pyrrolophanes with oppositely disposed pyrrole rings are thus far known only in the form of [2.2](2,5)pyrrolophane and some of its derivatives; see the review by W. W. Paudler, M. D. Bezoari in P. M. Keehn, S. M. Rosenfeld: The furan analogue of 2 is present in the crystal as a planar molecule; E. Vogel, M. Sicken, P. Rohrig, H. Schmickler, J. Lex, 0. Ermer, Angew. Chem. 100 (1988) 450; Angew. Chem. I n / . Ed. Engl. 27 (1988) 411. E. Vogel, M. Kocher, J. Lex, 0. Ermer, Isr. J. Chem. 29 (1989) 257 (David-Ginsburg-Memorial Issue).Comparably short hydrogen bonds between N atoms have, to our knowledge. thus Tar only been observed in "proton sponges" in protonated form, see H. A.

N-Oxazolidinoyl Diene Iron(0) Tricarbonyl Complexes: Preparation by Diastereoselective Complexation and Synthetic Applications

“…The melting point determined for 16b was achieved using an open capillary tube on a melting point apparatus and was uncorrected. In general, we did not observe peaks corresponding to the carbon nuclei of the iron(0) tricarbonyl units of the diene complexes in 13 C NMR spectra. Their presence was established by the chemical shifts of vinylic hydrogens in 1 H NMR spectra, by the appropriate absorbances in IR spectra, and by accurate high-resolution mass spectra.…”

“…Similarly, a racemic η 4 -hydroxy diene iron tricarbonyl complex was esterified with (−)-camphanoyl chloride and one of the resulting diastereomers was isolated by fractional recrystallization. 13 Enzymatic resolutions of functionalized η 4 -iron tricarbonyl complexes have also been achieved. 14,15 Finally, a more modern approach to synthesize a chiral nonracemic η 4 -formyldiene iron tricarbonyl complex was described by Donaldson Sharpless dihydroxylation of a known octadienoate (Scheme 1).…”

“…Crude reaction products were purified by flash chromatography using silica gel (32−63; median pore diameter, 60 Å). 1 H NMR spectra were recorded on a Bruker FT spectrometer at 400 MHz; 13 C NMR spectra were recorded on the same spectrometer at 100 MHz. CDCl 3 was used as the solvent in standard 5 mm diameter tubes.…”

“…The crude oil was purified via column chromatography (silica, 40:1 hexanes/EtOAc containing 0.5% NEt 3 ) to afford vinylstannane S1 as a clear oil (521.6 mg, 92%). 1 H NMR (400 MHz): δ 0.88−1.04 (m with tin satellites, 15H), 1.28−1.45 (m, 9H), 1.48−1.52 (m, 6H), 2.40 (t with tin satellites, J Sn−H = 24.0 Hz, J = 1.9 Hz), 4.16 (q, 2H, J = 7.1 Hz), 5.96 (q, 1H, J Sn−H = 33.4 Hz, J = 1.9 Hz); 13 120 Sn: 405.1810, found 405.1806. This data matches that previously reported for this compound.…”

On the Diastereoselectivity of the Complexation of Ketopinic Acid-Derived 2-Acyloxy-1,3-cyclohexadienes and the Configurational Stability of Dienol-Fe(CO)3 Complexes. A Case Study

“…In principle, there are four conceptually different approaches to synthesize planar chiral η 4 -diene-Fe­(CO) 3 complexes in nonracemic form. These are (1) resolution of racemates (either by physical, chemical, or enzymatic means); (2) enantioselective transformation of prochiral complexes; (3) direct enantioselective complexation; and (4) diastereoselective complexation of (temporarily) chirally modified substrates …”