The effect of 1,5-bridging on the solvolytic behavior of the bicyclo[3.1.0]hex-2-yl cation

Propellanes. 17. Bridgehead olefins via solvolysis of 10,10-dibromo[4.3.1]propellanes

“…The x-ray structure (see Figure 1 for a drawing of the final model) shows that the conformation of the nine-membered ring of 19 closely resembles the "twisted chair boat" (TCB) conformation found for cyclononylamine hydrobromide11 and cyclononanone. 12 The bond angles in all three structures generally agree; however, the average bond distances for the medium ring of 19 are significantly shorter (mean value 1.513 Á) than those for both cyclononylamine hydrobromide (mean value 1.532 Á) and cyclononanone (mean value 1.533 Á).…”

“…5-Bromomethylenecyclononanone (3): 21 mg (5.4%). d. l,6-Diacetoxy-10a-bromobicyclo[4.3.1]decane (20): 299 mg (53%), mp73-74 °C (hexane); IR (CC14) 1730, 1250cm-1; NMR already reported;4f l3C NMR (CDC13) 169.6, 124.4, 83.9,66.2,38.1, 36.3, 22.4, 20.9; mass spectrum (16 eV) parent ion not detected (m/e 332), but observed were peaks at m/e (rel int) 232 (4, P -Ac20), 230 (4, P -Ac20), 214 (17), 212 (17), 203 (6), 201 (6), 190 (19), 188 (19), 151 (95), 133 (37), 43 (100). Anal.…”

“…Preparation of 5-Bromomethylenecyclononanone-2,4-dinitrophenylhydrazone (19). Derivative 19 was synthesized via a literature procedure31 in 85% yield: mp 164-165 °C (chloroform); IR (KBr) 3320, 1622, 1590, 1522, 1336, 836 cm-'; NMR (CDC13) 9.07 (d, 1 , X portion of AMX, Jmx = 2.5 Hz), 8.25 (dd, 1 , M portion, Am = 10 Hz), 7.87 (d, 1 , A portion), 5.87 (s, 1 H), 2.9-1.5 (m, 14 ), 1.25 (s, NH).…”

“…Found: C, 50.52; , 6.20. e. 1 -Hydroxy-6-acetoxy-1 -bromobicyclo[4.3.1 [decane (23): 12 mg (2.5%); mp 87-88 °C (ether/hexane); 1R and 1H NMR already reported;4f mass spectrum (14 eV) parent ion not detected (m/e 290), but observed peaks were at m/e (rel int.) 232 (12, P -HOAc), 230 (12, P -HOAc), 214 (7), 212 (7), 203 (19), 201 (20), 190 (37), 188 (37), 151 (100), 133 (20), 43 (69). Anal.…”

“…Attempted dissolution of the crude solvolysate from 4 in 95% aqueous acetone led to a precipitate which proved to be bicyclic diol 9, the stereochemistry of which was unequivocally proven via correlation with 32 (i.e., hydrolysis of 32 amounts than the analogous diol 9. However, a careful investigation of the hydrolysis of 1 showed that the product ratios were dependent upon reaction time and amounts of silver and could find no evidence for an epimer of 3.10 Finally, the stereochemistry of 3 (and via hydrogenative correlation, 6) was determined by a single crystal x-ray analysis of the 2,4-dinitrophenylhydrazone derivative (19). The stereochemistry of 16 is presumed on the basis of the structure of 36.…”