Anionic N-heterocyclic carbenes derived from sydnone imines such as molsidomine. Trapping reactions with selenium, palladium, and gold

Abstract

Anionic N-heterocyclic carbenes derived from sydnone imines such as molsidomine. Trapping reactions with selenium, palladium, and gold.

Sulfur, mercury, and boron adducts of sydnone imine derived anionic N-heterocyclic carbenes

“…These complexes supplement the complexes 16 (Scheme 4) in which the gold is directly attached to C4 of the sydnone imines and which we described earlier. 16 Although the complexes 27a,b are stable enough to survive purication by column chromatography, gold complexes with the transition metal directly bound to the C4 carbene carbon atom are far more stable. The suldes were also stabilized as mercury complexes 28a,b which were formed on exposure of the suldes with mercury(II)chloride.…”

“…4(2), C4-S1: 171.6(2), S1-Hg1: 240.42(6), N6-Hg1: 247.27 17, N32-N33: 132.9(2), N33-C34: 134.8(2), C34-C35: 139.8 3, C35-N36: 132.4 3, N36-C37: 138.1(2), C37-O37: 122.8(2), C34-S31: 171. 4(2), S31-Hg1: 239.19(6), N36-Hg1: 251.07 17 16, C1-S1: 166.56 (12), C1-C2: 151.61 (16), C2-O2: 121.74 (15), C2-N3: 137.07 (16), N3-C4: 139.51 (16), C4-O4: 120.04 (16), S1-H9A: 264 pm.…”

“…The sydnone imine anion 12 (Z ¼ NR), usually stabilized by Li + , can be deuterated (13) and trapped by selenium, followed by methylation to give 14. 16 It forms palladium as well as gold complexes such as 15 and 16. 16 Iminium salts of formimidate are able to formylate the sydnone imine anions to yield 17, 17 and the treatment with aldehydes give alcohols such as 18.…”

“…16 It forms palladium as well as gold complexes such as 15 and 16. 16 Iminium salts of formimidate are able to formylate the sydnone imine anions to yield 17, 17 and the treatment with aldehydes give alcohols such as 18. 18 Trapping with isocyanates give amides (19), 19 and treatment with chlorodiphenylphosphane give phosphorus adducts like 20.…”

Anionic N-heterocyclic carbenes by decarboxylation of sydnone-4-carboxylates

“…19 Sydnone imine carbenes have been described recently. 20 According to a very recently introduced quantitative analysis of factors influencing the ease of formation of oxa-and thia-N-heterocyclic carbenes, N-phenylsydnone has a CREF (carbene relative energy of formation) index value of 0.572 which is between the values of 3 (Ar = Ph; 0.600) and 5 (Ar = Me; 0.547). 21 Scheme 3.…”