Ag+-catalyzed rearrangements. XIII. Mechanistic aspects of the silver(I)-promoted rearrangements of tricyclo[4.1.0.02,7]heptane derivatives. Deuterium isotope effect studies and independent generation of argento carbonium ions

Abstract

Kinetic deuterium isotope effects have been determined for the Ag+-catalyzed rearrangements of 1,7dideuterio-(lb), 1 -deuterio-7-methyl-(3b), and 1 -trideuteriomethyltricyclo[4.1.0.0 2'7]heptanes (8). Dideuterio analog la exhibited a faster rate of isomerization to 1,3-cycloheptadiene-2,3-d2 than its protio counterpart, thereby giving rise to an inverse fractionation factor (ks/kv = 0.847). A similar rearrangement of 3b revealed that the isomeric ethylidenecyclohexenes 4b and 5b as well as 2-methylcycloheptadiene 6b were also produced under the control

Molybdenum(II)-Catalyzed Allylation of Electron-Rich Aromatics and Heteroaromatics

“…1-Phenoxycyclohex-1-ene (107). To a stirred solution of cyclohex-2-en-1-ol (500 mg, 5.10 mmol), phenol ( 27 ) (590 mg, 6.27 mmol), and triphenylphosphine (1.638 g, 6.25 mmol) in THF (30 mL) at −20 °C was added dropwise diethyl azodicarboxylate (1.088 g, 6.25 mmol). The reaction mixture was allowed to warm to room temperature and the stirring continued for 4 h. The solvent was removed under reduced pressure, and the residue was extracted with hexane (3 × 20 mL).…”

Unexpected Skeletal Rearrangement in the Gold(I)/Silver(I)-Catalyzed Conversion of 7-Aryl-1,6-enynes to Bicyclo[3.2.0]hept-6-enes via Hidden Brønsted Acid Catalysis

“…From these observations, we hypothesized that (1) 7b was the 2,2-dimethyl-7-phenyl-1,6-enyne regioisomer of 7a resulting from transposition of the olefinc CH (C6) and CPh (C7) alkene carbon atoms and (2) silver was intimately involved in the scrambling process that led to formation of 7b . This latter hypothesis was influenced by the work of Paquette, who described the silver­(I)-catalyzed skeletal rearrangement of bicyclo­[4.1.0.0 2,7 ]­heptanes to form a range of substitution-dependent products including bicyclo[4.1.0]­heptenes and bicyclo[3.2.0]­heptenes, and it appeared plausible that a similar reaction manifold might be accessed via interaction of silver with the bicyclo[3.2.0]­heptene intermediate 3 or 5 .…”

Central and lateral bicyclo[1.1.0]butane bond cleavage with subsequent Wagner-Meerwein rearrangements or carbene formation in the 185-nm photolysis of tricyclo[3.1.0.02,6]hexane, tricyclo[4.1.0.02,7]heptane, and tricyclo[5.1.0.02,8]octane

“…NMR (CDC13, 200 MHz) b 1.15-1.25 (m, 1 , 8-H), 1.25-1.33 (m, 4 H, 4-H, 5-H), 1.63-1.74 (m, 4 H, 3-H, 6-H), 2.75-2.83 (m, 2 , 2-H, (12), 44 (23), 42 (21), 41 (29), 39 (40). For capillary GC conditions, cf.…”