Left handed GDPs

Formation, structure, and reactivities of 1:1 adducts between quadricyclane and (η5-cyclopentadienyl)(1,2-diphenyl- or -dimethoxycarbonyl-1,2-ethenedithiolato)rhodium(III)

“…This reaction is also one example of the addition reactions due to the unsaturation of the metalladicalcogenolene ring [3][4][5][6][7]. This addition reaction was also unique because it thermally caused the catalytic isomerization from Q to NBD.…”

“…Skeletal rearrangements of the hydrocarbon moiety were confirmed in the formation of adducts and in their photo-dissociScheme 6. ation according to deuterium labeling experiments. We conclude that such reversible addition and dissociation reactions of metalladicalcogenolene ring are caused by the coexistence of the aromaticity [2] and the unsaturation [3][4][5][6][7] of the metalladicalcogenolene ring.…”

“…Based on the results that the hydrocarbon unit of the adduct is not eliminated as a NBD and that the adduct itself has some activity, the following processes can be expected: (i) after the initial interaction between the adduct and Q, an electron transfer from Q to the adduct occurs, (ii) subsequent bond formation between Rh and a carbon atom of Q results in the ring expansion from 5 to 6 rings due to the Rh-S bond cleavage, accompanied by rearrangement of the carbon skeleton occurs, and (iii) the pre-adduct (1:2 adduct) with a corner-metalated cation [17] is formed, and then the norbornene unit of pre-adduct is eliminated by the intramolecular attack of the free sulfur atom. In another report, we have reported such ring expansion reaction by the reaction of the 1:1 alkylidene adduct with P(OMe) 3 to give the 1:2 (or 1:1:1) adduct [Co(Cp)(S 2 C 2 (CN) 2 )(CH 2 )(P(OMe) 3 )] (Eq. (4)) [18].…”

“…The remarkable features of this metalladichalcogenolene ring result from the coexistence of aromatic character due to a conjugated system with 6p electrons [2], and unsaturation especially at the central metal and at the chalcogen atoms in the ring [3].…”

“…Found: C, 45.98; H, 4.17%. 1 H NMR (270 MHz, CDCl3 , vs. TMS): 1.33 (ddd, J gem ¼ 13:1, J 6-5 ¼ 6:7, J 6-7 ¼ 1:8 Hz, 1H, H 6-endo ), 1.51 (dd, J gem ¼ 13:1, J 6-1 ¼ 3:9 Hz, 1H, H 6-exo ), 2.77 (dd, J 1-6 ¼ 3:9, J 1-2 ¼ 3:3 Hz, 1H, H 1 ), 2.86 (dd, J 5-6 ¼ 6:7, J 3-2 ¼ 1:9 Hz, 1H, H 5-endo ), 2.92 (d, J 4-3 ¼ 3:3 Hz, 1H, H 4 ), 3.34 (dd, J 7-6 ¼ 1:9, J 7-5 ¼ 1:5 Hz, 1H, H 7 ), 3.73 (s, 3H, OMe), 3.86 (s, 3H, OMe), 5.28 (s, 5H, Cp), 5.93 (dd, J 3-2 ¼ 5:9, J 3-4 ¼ 3:3 Hz, 1H, H 3 ), 6.35 (dd, J 2-3 ¼ 5:9, J 2-1 ¼ 3:3 Hz, 1H, H 2 ) 13. C{ 1 H} NMR (67.94 MHz, CDCl 3 , vs. TMS): 35.5 (C 6 of C 7 H 8 ), 51.4 (C 1 of C 7 H 8 ), 52.0 (C 5 of C 7 H 8 ), 52.4 (OMe), 53.1 (OMe), 54.5 (C 4 of C 7 H 8 ), 67.0 (d, J Rh-C ¼ 25:3 Hz, C 7 of C 7 H 8 ), 114.1 (dithiolene-C), 132.1 (C 3 of C 7 H 8 ), 142.5 (C 2 of C 7 H 8 ), 179.7 (dithiolene-C), 89.5 (d, J Rh-C ¼ 3:7 Hz, Cp), 163.1 (C@O), and 168.3 (C@O).…”