Correction. Stereochemistry of Radical Additions of Bromotrichloromethane to Some Cyclic Olefins

Relative reactivities and stereochemistry of addition of iodoperfluoroalkanes to cyclic olefins

“…Twisting of the ring into twist-boat forms was observed, consistent with dipole moments and other data.8•4 Again, the addition of BrCCls conforms to this behavior. [5][6][7][8][9][10][11] Cycloheptane has twist-chair and twist-boat conformations as its lowest energy forms.12 The barrier to flipping from chair to boat family is 8.50 kcal/mol and the twist-boat is 2.49 kcal/mol less stable than the twist-chair. Due to pseudorotation, a substituent in one position may pass to every other, as detailed by Hendrickson.12 In 1,2-disubstituted cycloheptanes it is possible to distinguish between two cis and two trans forms, but by pseudorotation these reduce to only one of each, separated by a high energy barrier.…”

“…The product was extracted with 10 ml of dichloromethane three times, dried over magnesium sulfate, and distilled to give 6 and 7, bp 73°( 18 mm), n26D 1.3856, 2.6 g (55% of theory). Glpc analysis (5 ft XE-60 silicone oil column, 15% on Chromosorb W, 115°, 25-psi helium) gave peaks at 5.8 (53.5%) and 6.2 min (46.5%). Similar results were obtained with a 10-ft SE-30 silicone oil column or a 4 ft "UCON Polar" LB550-X column, which gave peaks at 12.4 (2.15%), 14.0 (54.1%), and 15.3 min (43.8%); ir (KBr, liquid film) rcn-c 3040, vch 2960, 2940, 2880, "oc 1660 (w), 0 1480, 1455, 1350, pow 1220, 1180, 1120, bands at 1015, 982, 955, 940, 920, 908, 895, 845, 825, 775, 755, 745, 738, 722, and 710 cm-1, weak bands appeared at 690, 670, 655, and 535 cm-1.…”

“…The twist-boat conformation was subsequently observed by other workers in the analogous case of trans-l-bromo-2-trichloromethylcyclohexane. 5 While reactions of cycloheptene and cfs-cyclooctene with carbon tetrachloride or bromotrichloromethane have been reported,5-7 addition of Rpl to these cyclic olefins has not been investigated. We were particularly interested in the influence that the greater mobility of these medium-size rings would have on the relative ease of addition, since cyclopentene and cyclohexene were unusually sluggish in their reactions with Rpl.…”

Radical additions of bromodichloronitromethane to cyclic olefins

“…The photoinitiated addition of bromodichloronitromethane to cyclohexene gave isomeric results similar to that reported for bromotrichloromethane. 2 The major product (13%) was a 40:60 mixture of cis-and trans-1bromo-2-(dichloronitromethyl)cyclohexane (I). This ratio was an average (±5%) obtained from ten reactions.…”