Photochemistry of bicyclo[3.2.1]octan-6-ones. Stereoselectivity of hydrogen transfer in disproportionation of biradical intermediates

Absence of stereoelectronic control in the photochemistry of two diastereomeric .beta.,.gamma.-epoxy ketones

“…The white solid had a longer retention time (column B) than ketone 5 and was characterized as 8: mp 84.5-87.5 °C; IR 2950 (s), 2855 (w), 1753 (s), 1475 and 1465 (w), 1395 (w), 1361 (m), 1135 (w), 1105 (w), 940 (w), 880 (vw) cm"1; NMR 2.83 (s, with some overlap of adjacent m, total ~2.2 H), 2.60-1.20 (m, ~9 ), 0.88 (s, 9 H); mass spectrum, m/e 208.1466 (M+, caled for C]3H2o02, 208.1463). exo-3-tert-Butylspiro[b¡cyclo[3.2.1 ]octane-8,1 '-cyclopropan]-6-one (11). A mixture of zinc-copper couple (260 mg, ~3.6 mg-atom Zn; Ventron-Alfa) and iodine (2-3 tiny crystals) in anhydrous ether (3.6 mL) was stirred under nitrogen and warmed to reflux temperature.…”

Photochemistry of two .beta.,.beta.'-epoxy ketones, 3-oxatricyclo[3.2.1.02,4]octan-8-one and 3-oxatricyclo[3.3.1.02.4]nonan-9-one. Intramolecular reactions of .alpha.,.beta.-unsaturated aldehydo ketenes

“…At least four minor products (each <3%, based on 1) were detected in the NMR spectrum and/or VPC analysis of the crude photolysate. One of these appeared to be 7 (methoxy signal at 3.3; see C below) and a second one (isolated at retention time 12-13 min) the cis isomer of 6: IR 2944 (w), 2911 (m), 2840 (m), 2810 (w), 2710 (w), 1742 (s), 1684 (s), 1608 (w), 1432 (m), 1358 (w), 1200 (m), 1158 (m) cm"1; NMR 1.5-2.6 (m), 3.63 (s), 6.5 (m), 10.00 (d, J = 7.5 Hz).…”

Umlagerungen von 1,4,4‐ und 2,2,5‐Trimethylbicyclo[3.2.1]oct‐6‐yl‐Kationen

“…N 6.87 Gef. N 6.94 1,4, Desarninierung oon 6 und 8: Zu 50 mg (0.25 mmol) Aminhydrochlorid in 10 ml Wasser gab man 52 mg (0.75 mmol) Natriumnitrit, stellte rnit 1 N HC104 pH = 3 ein (Glaselektrode) und riihrte 16 h bei Raumtemp. Die Losung wurde rnit Natriumchlorid geszttigt und zweimal rnit Ether ausgeschiittelt.…”