Jan. 30, 1961
C03I3IUNICATIONS TO THE
This investigation of the dehydrohalogenation of neoalkyl halides by strong base was made to elucidate the reaction mechanism. From the experimental data i t can be concluded that carbanions and/or strong bases attack and remove an a-hydrogen atom with displacement of halide (a-elimination) to form the carbene intermediate which gives cyc2opropanes by intrumolecular-insertion~a~cand olefins by rearrangement.4 Thus, neopentyl halides and sodium, sodamide in diethyl Carbitol, or phenyl sodium in decane give 1,l-dimethylcyclopropane, small amounts of 2methyl-2-butene, neopentane5 and corresponding substitution products (Table I).
EDITOR
benzene also was obtained.' These results support the proposed mechanism of the reaction. CHa
I
CHS-C-CD~CI
I
CHI PhKa CH3 CCl 1 C H 3 - Ib c : \
L
CH,
'D
Phh'ad 14' 82 4.3 71 PhNa 9.2 87 3.5 70 NaSHz 6.9 90 2.9 60 c1 Naf 51 82 7 60 Br PhKa 5.5 86 7.3 25 DMPT NaOMe ... 89 9 8510 a % composition. Products analyzed, separated and identified by V.P.C. Traces (
