The stereochemistry of organometallic compounds. XVIII. Tricarbonylchromium complexes of cis- and trans-1,3-Dimethylindan-5-amine

Abstract

cis- and trans-1,3-Dimethylindan-5-amines have been prepared and allowed to react with hexa-carbonylchromium. The stereochemistry of the tricarbonylchromium complexes so obtained is discussed.

Trikentramides A–D, Indole Alkaloids from the Australian Sponge Trikentrion flabelliforme

“…In contrast, the DP4 probability indicated that the experimental data for 10 were most consistent with the theoretical data calculated for the trans isomer (>99.9% probability). These assignments were consistent with results from previous studies of related molecules. , The theoretical NMR data for the cis isomer of 11 were most consistent with the experimental data of 11 , and again, the cis theoretical NMR data of 12 correlated with the experimental data of 12 (Supporting Information). …”

“…These assignments were consistent with results from previous studies of related molecules. 3,14 The theoretical NMR data for the cis isomer of 11 were most consistent with the experimental data of 11, and again, the cis theoretical NMR data of 12 correlated with the experimental data of 12 (Supporting Information). 28 The cyclopenta[g]indole structure class has rarely been reported, and the natural occurring trikentrins and herbindoles A−C are the only examples to date.…”

“…These assignments were consistent with results from previous studies of related molecules. 3,14 The theoretical NMR data for the cis isomer of 11 was most consistent with the experimental data of 11, and again, the cis theoretical NMR data of 12 correlated with the experimental data of 12 (Supporting Information). 28…”

“…3,6 Previous studies on the trikentrins (1−5) had shown that large 1 H NMR chemical shift differences between the diastereotopic H-7 methylene protons (Δδ H-7a/H-7b > 1) were indicative of the cyclopentenyl unit containing methyl groups with a cis orientation, whereas no or minimal differences (Δδ H-7a/H-7b < 0.5) were diagnostic for the trans isomer. 3,6,14 Trikentramides A, C, and D all had relatively large Δδ H-7a/H-7b (i.e., 1.29, 1.29, and 1.34, respectively), indicating that they all possessed the cis configuration at the C-6 and C-8 positions. Trikentramide B was assigned as having a trans configuration due to its small Δδ H-7a/H-7b value of 0.16.…”

“…The relative configurations for 9 – 12 were established by comparison of their 1 H NMR data to the known trikentrin analogues. , Previous studies on the trikentrins ( 1 – 5 ) had shown that large 1 H NMR chemical shift differences between the diastereotopic H-7 methylene protons (Δδ H‑7a/H‑7b > 1) were indicative of the cyclopentenyl unit containing methyl groups with a cis orientation, whereas no or minimal differences (Δδ H‑7a/H‑7b < 0.5) were diagnostic for the trans isomer. ,, Trikentramides A, C, and D all had relatively large Δδ H‑7a/H‑7b (i.e., 1.29, 1.29, and 1.34, respectively), indicating that they all possessed the cis configuration at the C-6 and C-8 positions. Trikentramide B was assigned as having a trans configuration due to its small Δδ H‑7a/H‑7b value of 0.16.…”