Rearrangements of 2-Bicyclo[3.2.0] heptyl Grignard Reagents ratio of 25/24 was 17/83 after 15 min; the ratio did not change after an additional 40 min at -100 "C. An additional 1.1 equiv of n-butyllithium was added. After 15 min the above ratio was 75/16; compound 26 w,ts also detected. The mixture was continually stirred at -100 "C; examination of aliquots showed that the amount of 24 decreased while the amount of butylated products (26 and 27) increased. The mixture was quenched with water after a total of 4 h after the second addition of n-CaHgLi. The mixture of products obtained contained phenylpropionitrile (25, 62%), abutyl-0-phenylpropionitrile (26, 19%), a-butyl-P-(p-butylphen-y1)propionitrile (27, 13%), and an unidentified product. Products were collected by preparative GLC.a-lButyl-j3-phenylpropionitrile (26): NMR (CDC13) 6 0.9 (t, 3, aliphatic H), 1.55 (m, 6, aliphatic H), 2.9 (m, 3, aliphatic H), 7.3 (m, 5, aromatic H).Anal. Calcd for C13H17N: C, 83.37, H, 9.15; N, 7.48. Found: C, 83.55; H, 9.05; N, 7.55. a-Butyl-8-(p-butylpheny1)propionitrile (27): NMR (CDCl3) 6 0.70-1.9 (m, 16, aliphatic H), 2.2 (m, 2, CHz), 2.85 (m, 3, aliphatic H), 7.2 (m, 4, aromatic H). Anal. Calcd for C17H25N: C, 83.89; H, 10.35. Found: C, 83.79; H, 10.60.p-Iodobenzylnitrile (28). E~a m i n a t i o n~~ of an aliquot, quenched with water taken after 15 min from reaction of 2tIz7 with 1 equiv of n-C4HgLi at -100 "C, showed the ratio of benzylnitrile to starting material (28) to be 80/20; starting material immediately disappeared upon addition of an additional 0.5 equiv of n-C4HgLi. Attempts to trap the anionic products from the reaction mixture with cyclohexanone gave a multicomponent mixture (GLC) which was not resolved. (24) Shown by coinjection of an authentic sample prepared from benzyl nitrile (1 equiv), sodium hydride (2 equiv), and methyl iodide (2 equiv) in dirnethylformamide: bp 226 OC (754 mm); n Z 5~ 1.5016 (lit.25 bp 232The Grignard reagent (12) from 2-bromobicyclo[3.2.0]heptane undergoes a ring cleavage rearrangement to cyclopentenylethyl (13) and cycloheptenyl (14) Grignard reagents. Grignard 14 is slowly converted to 13. The rate of rearrangement of 12 is thought to be somewhat retarded by geometric restrictions introduced by the bicyclic skeleton. The facility of the rearrangement of 12 4 14 may indicate that the preferred transition state for rearrangement is nonplanar. Rearrangement of the Grignard reagent 25 from 3-chlorotricyclo[5.3.0.02~6]decane occurs in analogous fashion. Grignard reagents 31 from 2-bromo-6-alkoxybicyclo[3.2.0]heptanes decompose with elimination of the alkoxy group and ring cleavage to 3-vinylcyclopentene and 1,4-cycloheptadiene.
