Two-step 1,2-shifts by β-cleavage of carbenium ions and recombination in friedel-crafts reactions of 2-ferf-butyl-l-tosylaziridines

Article abstract of DOI:10.1021/jo980774m

Alcl₃-induced ring cleavage of two 2-tert-butyl-l-tosylaziridines in benzene (PhH) or anisole (AnH) generates carbenium ions (CIs). Subsequent neopentyl rearrangement forms CIs 3a,b, whose β-cleavage generates ⁺CH₂NTsAlCl₃^- (14) and an alkene. The intermediate 14 can recombine with the alkene at either C=C carbon, resulting in a reversal of the cleavage (3a,b) or in a formal 1,2shift (CIs 12a,b). AnH rapidly removes 14 from these interconverting systems by formation of a methoxybenzylamide species that undergoes fragmentation into TsNHAlCl₃^- and methoxybenzyl cation, which gives dianisylmethane (main product). PhH reacts slowly with 14, leaving CIs 3a,b and 12a,b more time for other reactions. Unreacted 14 can even be trapped by AnH at the end of a PhH run. Protonation of each alkene forms N-free CIs that react with PhH and AnH. Replacing tosyl in one of the aziridines by benzoyl makes the β-cleavage markedly slower than both the classic phenyl shift and the internal trapping of CIs.

Full text of DOI:10.1021/jo980774m

J . Org. Chem. 1998, 63, 7749-7752
7749
Tw o-Step 1,2-Sh ifts by â-Clea va ge of Ca r ben iu m Ion s a n d
Recom bin a tion in F r ied el-Cr a fts Rea ction s of
2-ter t-Bu tyl-1-tosyla zir id in es1
Konstantinos Bellos and Helmut Stamm*
Faculty of Pharmacy, University of Heidelberg, Neuenheimer Feld 346, D-69120 Heidelberg, Germany
Received April 24, 1998
AlCl3-induced ring cleavage of two 2-tert-butyl-1-tosylaziridines in benzene (PhH) or anisole (AnH)
generates carbenium ions (CIs). Subsequent neopentyl rearrangement forms CIs 3a ,b, whose
â-cleavage generates CH2NTsAlCl3- (14) and an alkene. The intermediate 14 can recombine with
+
the alkene at either CdC carbon, resulting in a reversal of the cleavage (3a ,b) or in a formal 1,2-
shift (CIs 12a ,b). AnH rapidly removes 14 from these interconverting systems by formation of a
-
methoxybenzylamide species that undergoes fragmentation into TsNHAlCl3 and methoxybenzyl
cation, which gives dianisylmethane (main product). PhH reacts slowly with 14, leaving CIs 3a ,b
and 12a ,b more time for other reactions. Unreacted 14 can even be trapped by AnH at the end of
a PhH run. Protonation of each alkene forms N-free CIs that react with PhH and AnH. Replacing
tosyl in one of the aziridines by benzoyl makes the â-cleavage markedly slower than both the classic
phenyl shift and the internal trapping of CIs.
Friedel-Crafts (FC) reactions with activated aziridines
often take complicated courses and rarely lead to struc-
tures Ar-C-C-N.2-6 Classic 1,2-shifts and other reac-
tions typical of carbenium ions were found with N-sulfonyl-
aziridines.4-6 The intramolecular nature of 1,2-shifts in
carbenium ions is well established. A two-step 1,2-shift
by â-cleavage and subsequent recombination is now
described, and the structural prerequisite for other
examples is given.
essential topic of this report, a two-step 1,2-shift, is
demonstrated by products 7 and 8 in runs 1 and 2
because they require precursor 12a or 13 (Scheme 2),
respectively, which are interconnected by a simple hy-
dride shift. Formation of 12a by one or more classic 1,2-
shifts is not compatible with the observed strong influ-
ence of the solvent: the yield of 7 and also that of 8 was
much higher in PhH than in anisole AnH. One might
expect the opposite for the deprotonation of 12a . A two-
step 1,2-shift (Scheme 2, top left) can easily explain this
finding by competing reactions of intermediates 14, and
15a , whose formation is already proven by other prod-
ucts. In fact, benzylamide 9P can only have come from
the reaction of PhH with methylenimonium zwitterion
14. This is clear evidence for the â-cleavage 3a f 14 +
15a , despite its very uncommon feature. The arising
iminium ion is destabilized by electron withdrawal, in
contrast to the product of the well-known7 common
â-cleavage. Only one similar cleavage seems to be
Resu lts a n d Discu ssion
FC reactions of aziridines 1a ,b are listed in Table 1.
First, carbenium ions 2a ,b are generated, as can be
deduced from the product structures depicted in Schemes
1 and 2. Incorporation of a solvent molecule (6, 9-11,
and 18) was mainly found in fragments of 2a ,b. This
incorporation is indicated by Ar in the formula and by
the addition of P (phenyl) or A (anisyl) to the product
number. Structure A was nearly always para; only 10A
and 11bA were isolated as a mixture (1H NMR) with a
small amount of one or two additional isomers.
The sole reaction of 2a ,b, apart from the formation of
very little 4 in runs 1 and 2, was the neopentyl rear-
rangement 2a ,b f 3a ,b. The only classic reactions of
the new carbenium ions 3a ,b were deprotonation 3b f f
5b in runs 2-4, a little electrophilic substitution of
benzene (PhH) in run 1 (3a f f 6a P ), and a 1,2-phenyl
shift in 3b (see below). Steric shielding by the benzyl
group seems to slow down deprotonation of 3a . The
known8 so far, that of the proton analogue (AlCl3
-
replaced by H) of 3b. This peculiarity may be considered
to be responsible for an atypical 1,2-shift and will be a
prerequisite for further examples. It is this peculiar
electron withdrawal that makes 14 more reactive than,
for example, Eschenmoser’s salt and similar reagents.
This electron withdrawal enables 14 to attack both the
solvent (f f 9P ) and the alkene (15a f 12a ) entering
the path to 7 and 8 by attack on the latter. Attack on a
solvent molecule produced the AlCl3 adducts 9fAlCl3
with AnH much faster than with PhH, but only 9P fAlCl3
survived until hydrolysis (f 9P ). The AnH-derived
(1) (a) Aziridines, part 74. (b) For part 73, see: Lin, P. Y.; Stamm,
H. J . Chem. Res., in press. (c) For part 72, see: Mall, T.; Stamm, H. J .
Chem. Soc., Perkin Trans. 2 1997, 2135-2140.
-
9AfAlCl3 fragmented (cf. ref 6) into TsNHAlCl3 and
methoxybenzyl cation, whose reaction with AnH gave
dianisylmethane 10A, the main product of run 2. The
(2) Heine, H. W.; Proctor, Z. J . Org. Chem. 1958, 23, 1554-1556.
(3) Mall, T.; Buchholz, B.; Stamm, H. Arch. Pharm. (Weinheim, Ger.)
1994, 327, 377-380 and references therein.
(4) (a) Genssler, W. J .; Rockett, J . C. J . Am. Chem. Soc. 1955, 77,
3262-3264. (b) Genssler, W. J .; Dheer, S. K., J r. J . Org. Chem. 1981,
46, 4051-4057.
(7) (a) Bethell, D. Carbocations and Carbanions. Stoddart, J . F., Ed.
In Comprehensive Organic Chemistry; Baron, D., Ollis, W. D., Eds.
Pergamon Press: Oxford, 1979; Vol. 1, Chapter 2.7, p 434. (b) Grob,
C. A. Angew. Chem. 1969, 81, 543-554; Angew. Chem., Int. Ed. Engl.
1969, 81, 535-546.
(5) Kurokawa, S.; Anderson, A. G., J r. Bull. Chem. Soc. J pn. 1983,
56, 2059-2064.
(6) Stamm, H.; Onistschenko, A.; Buchholz, B.; Mall, T. J . Org.
Chem. 1989, 54, 193-199.
(8) Bellos, K.; Stamm, H. J . Org. Chem. 1995, 60, 5661-5666.
10.1021/jo980774m CCC: $15.00 © 1998 American Chemical Society
Published on Web 10/02/1998

7750 J . Org. Chem., Vol. 63, No. 22, 1998
Ta ble 1. Rea ction s of 1a ,b w ith AlCl3 in Ben zen e (P h H) or An isole (An H)a
yields (%) of productse
Bellos and Stamm
run
4
5b
6a P
7
8
9c
10A
TsNH2
11d
15b
17b
18A
19b
1
2
3
4
5
1a /PhH
1a /AnH
1b/PhH
1b/PhH
1b/AnH
2
tr
7
56
16
3
tr
5
tr
6
22
75
75
66
100
tr
9
7
75
37
46
50
12
5
10
3
9
5
1.5
tr
86
62
a
b
Reaction conditions: 20 min under cooling with ice; 4 mmol of 1a ,b; 6 mmol of AlCl3; 40 mL of PhH or AnH. 5a in run 2; 5b in runs
3 and 4. c 9P in runs 1, 3, and 4; 9A in run 2. 11a A in run 2; 11bP in runs 3 and 4; 11bA in run 5. e tr ) trace.
d
Sch em e 1
Sch em e 2
eliminated TsNHAlCl3- was hydrolyzed to TsNH2 in the
same yield.
There is no reason why 14 and alkene 15a (Scheme 2)
should form only 12a and no 3a . Extending this line of
reasoning suggests reversibility for both reactions of 14
with 15a , whereas the reaction of 14 with the solvent is
(almost) irreversible under the experimental conditions.
Thus, the slow reaction of 14 with PhH gave sufficient
time for other reactions both of 3a (f 6a P ) and 12a
(products 7 and 8), whereas the fast trapping of 14 by
AnH prevented the formation of 6a A and nearly that of
7 and 8. Part of 14 seemed even to remain intact in run
1 (see below) until the run was quenched with ice, thus
providing 22% of TsNH2. The possible intermediate
TsNdCH2 is known to be labile.9
Protonation of alkene 15a can generate carbenium ions
20a and 21a (Scheme 2). The nitrogen-free product 11a A
arose from arylation of the sterically less demanding
isomer 21a . The yield of this sole product derived from
15a without participation of 14 was only half the yields
of 10A and TsNH2. This fact points to a loss of 15a or of
its styrene isomer 16, which can arise from 20a , during
workup.10 A similar loss of 15a or 16 in run 1 is indicated
by the isolation of 9P and TsNH2 despite the absence of
1
11a P . The structure of 11a A follows from the H NMR
spectrum for CH-CH2 that forms nearly an AA′X system
whose decoupling shows CH2 to be AX. Ring current
effects make CH-CH nearly isochronous and shift the
second CH2 signal downfield by more than 0.7 ppm.
Apart from steps 1b f 2b f 3b, only reactions of 1a
have been discussed so far. The aziridine 1b (runs 3-5)
behaved analogously, with a few variations that more or
less may have been expected. One of them, the produc-
tion of 19b, is discussed below. There is also good
evidence for the two-step 1,2-shift (Scheme 2, top left)
3b f 12b. Deprotonation of 12b can only provide 17b,
whereas 12a gave 7 in higher yields (runs 1 and 2).
â-Cleavage 3b f 14 + 15b was unequivocally confirmed
by detection of 15b (runs 4-5). As discussed above, 14
reacted in runs 3-5 giving unchanged or nearly un-
changed yields of 9A,P and an increased yield of 10A.
The equilibrium for protonated alkene 15b has to be on
the side of benzyl cation 20b. For steric reasons, PhH
(9) Kinoshita, H.; Inomata, K.; Hayashi, M.; Kondon, I.; Kotake, H.
Chem. Lett. 1986, 1033-1036.
(10) The volatility of 1-tert-butylstyrene (isomer of 15a and 16) is
known (see Experimental Section of ref 11). The lower (C11) homologue
15b has been lost in another reaction of 1b8. 15b is known,12 and the
data given12a suggest a coevaporation with solvent during workup.
Formation of 11a P (not detected) from 21a may suffer not only from
the low FC reactivity of PhH but also from the conversion 15a f 16.

Two-Step 1,2-Shifts by â-Cleavage of Carbenium Ions
J . Org. Chem., Vol. 63, No. 22, 1998 7751
Sch em e 3
25 were found (about 9% taken together). Products
arising from 25 without cleavage totalled about 63%.
Cleavages of 25 and of its analogue 3b have to compete
with 1,2-shifts of phenyl (indans 19b and c, 3-9% and
23%, respectively). Although the cleavage of 25 had to
furthermore compete with cyclizations (26 and 28), the
amount of phenyl shifts occurring in 25 was greater than
in 3b. Clearly, â-cleavage of 25 is slower than that of
3b.
The structure of 28 followed from the spectra.
A
geminal proton coupling of 8.4 Hz is in accord with an
azetidine.14 The 1H NMR spectrum of 28 revealed a
contamination (about one-fifth) that is assumed to be 29
because the signals, especially the aliphatic ones, were
very similar or identical to the signals for 28. Only the
chemical shift of one methyl group changed from 1.80
ppm (28) to 0.89 ppm. The total yield of 28 and 29 was
29%.
Exp er im en ta l Section
Gen er a l Meth od s a n d Ma ter ia ls. 1H NMR spectra were
recorded from CDCl3 solutions containing TMS. IR spectra
were recorded from KBr tablets unless otherwise stated.
Column chromatography (chr) (column dimensions 3 × 60 cm)
was performed with 0.063-0.2 mm silica gel (Merck). Pre-
parative layer chromatography (PLC) was performed with
silica gel 60 F254 (Merck 5717), 20 × 20 cm, 2 mm thick; zones
were extracted with hot ethyl acetate.
was exclusively attacked by the minor equilibrium com-
ponent 21b (f 11bP ), whereas AnH reacted mainly with
the major component 21b, giving more 18A than 11bA.
Indan 19b is assumed to arise from consecutive 1,2-shifts
3b f 22 f 23, followed by an intramolecular electrophilic
substitution in the ortho position.
Survival of some 14 in PhH was unequivocally proven
in an exact repetition of run 3. Unreacted 14 was
trapped by AnH (30 mL) that was added prior to
quenching. After the reaction was continued for 10 min,
27% of 10A was found. The incomplete conversion of 14
can be ascribed to the short reaction time and the low
temperature of the runs shown in Table 1 and also to a
more moderate FC reactivity compared to that of 21b
when one considers the low concentration and the ap-
parently higher steric demands of the latter. This points
to a pronounced iminium character of 14 with negligible
mesomerism, although other reasons for a moderate FC
reactivity are conceivable. The reactivity of 14 may gain
practical value when it can be generated from TsNdCH2.
The electron withdrawal power which is essential for
the two-step 1,2-shift can also be provided by a benzoyl
group, as could be shown by a single run with 1c in PhH
despite the strong tendency2,3 to internally trap the
carbenium ions derived from N-acylaziridines. The N-
acylaziridines coordinate a Lewis acid to the oxygen.3,8,13
Thus, for this run with 1c (Sheme 3), benzoyl counter-
parts (BCP) of intermediates shown already in Schemes
Sta r tin g Ma ter ia ls a n d Kn ow n P r od u cts. The aziri-
dines 1a ,b15 and 1c16 are known. The products 4, 5a -c, 15b,
24, and 26 are already described.8
Gen er a l Meth od of Rea ction s. For details, see Table 1.
The reaction mixtures were continuously stirred. Reactant
1a ,b was added at once to a stirred mixture of PhH or AnH
and AlCl3. The reactions were quenched by the addition of
ice. This mixture was taken up in 300 mL of ethyl acetate
and washed with water three times. The residue obtained by
evaporation was subjected to chr; details are given with each
run.
Ru n 1. Chr with CH2Cl2 provided 50 mg of a mixture
consisting (1H NMR) of 28 mg (2%) of 4 and 22 mg of 7.
Further elution yielded 720 mg of 7, 120 mg of mixture I, 90
mg of 6a P , and 50 mg (5%) of 9P . Elution with ethyl acetate
gave 152 mg (11%) of TsNH2. PLC (toluene-ethyl acetate,
20:1) of mixture I provided (from bottom to top) 36 mg (total
126 mg, corresponding to 7%) of 6a P , 34 mg (total 776 mg,
corresponding to 56%) of 7, and 44 mg (3%) of 8.
N-(2-Ben zyl-3-p h en yl-2,3,3-t r im et h ylb u t yl)t olu en e-4-
su lfon a m id e (6a P ): mp 158-160 °C; IR 3265, 1328, 1162
1
cm-1; H NMR δ 0.97 (s, 3H), 1.06 (s, 3H), 1.13 (s, 3H), 2.43
(s, 3H), 2.59 (d, J ) 15.8 Hz, 1H), 2.75 (d, J ) 15.8 Hz, 1H),
2.85 (dd, J ) 12.4/6.6 Hz, 1H), 2.95 (dd, J ) 12.4/6.9 Hz, 1H),
4.36 (t, J ) 6.6 Hz, 1H), 7.03-7.35 (m, 12H), 7.67-7.74 (m,
2H). Anal. Calcd for C26H31NO2S: C, 74.07; H, 7.41; N, 3.32.
Found: C, 74.05; H, 7.23; N, 3.20.
-
1 and 2 have N(Ts)AlCl3- replaced by NdCPh-OAlCl3
(cf. ref 8).
N-(4-P h en yl-2,2,3-t r im et h yl-3-b u t en yl)t olu en e-4-su l-
fon a m id e (7): mp 106-108 °C; IR 3270, 1658, 1331, 1166
cm-1; 1H NMR δ 1.12 (s, 6H), 1.63 (d, J ) 1.1 Hz, 3H), 2.40 (s,
3H), 2.89 (d, J ) 6.1 Hz, 2H), 4.45 (t, J ) 6.0 Hz, 1H), 6.30 (s
br, 1H), 7.13-7.37 (m, 7H), 7.70-7.78 (m, 2H). Anal. Calcd
for C20H25NO2S: C, 69.94; H, 7.34; N, 4.08. Found: C, 69.86;
H, 7.41; N, 4.00.
The BCP of 2b either was internally trapped (oxazoline
24, 11%) or generated 25 (BCP of 3b). The latter cyclized
expectedly (26, 17%) and unexpectedly (azetidine 28), or
it underwent reactions as described for 3b, resulting in
the products shown in Scheme 1 (5c, 6%) or Scheme 2
(17c, 3% and 19c, 23%). Product 17c is derived from the
two-step 1,2-shift outlined in Scheme 3. Only two
products (17c and 29, see below) requiring â-cleavage of
N-(4-Met h ylp h en ylsu lfon yl)-2-p h en yl-3,4,4-t r im et h -
1
ylp yr r olid in e (8): mp 113-118 °C; IR 1350, 1162 cm-1; H
(11) Bellos, K.; Werry, J .; Assithianakis, P.; Weiss, R.; Mall, T.;
Bentz, G.; Stamm, H. J . Prakt. Chem. 1996, 338, 270-278.
(12) (a) Brewster, J . H.; Patterson, J .; Fidler, D. E. J . Am. Chem.
Soc. 1954, 76, 6368-6371. (b) Overberger, C. G.; Gainer, H. J . Am.
Chem. Soc. 1958, 80, 4561-4565.
(14) Lwowski, W. Structure of Small and Large Rings. In Compre-
hensive Heterocyclic Chemistry; Katritzky, A., Rees, C. W., Eds.;
Pergamon Press: Oxford, 1984: Vol. 1, p 10.
(15) Bellos, K.; Stamm, H.; Speth, D. J . Org. Chem. 1991, 56, 6846-
6849.
(16) Werry, J .; Stamm, H.; Lin, P.-Y.; Falkenstein, R.; Gries, S.;
Irngartinger, H. Tetrahedron 1989, 45, 5015-5028.
(13) Olah, G. A.; Szilagyi, P. J . J . Am. Chem. Soc. 1969, 91, 2949-
2955.

7752 J . Org. Chem., Vol. 63, No. 22, 1998
Bellos and Stamm
NMR δ 0.59 (s, 3H), 0.74 (d, J ) 6.8 Hz, 3H), 0.98 (s, 3H),
1.77 (dq, J ) 10.1/6.8 Hz, 1H), 2.38 (s, 3H), 3.35 (d, J ) 10.7
Hz, 1H), 3.61 (d, J ) 10.7 Hz, 1H), 4.09 (d, J ) 10.1 Hz, 1H),
2-Meth yl-2-m eth oxyp h en yl-2-p h en ylbu ta n e (11bA) (in
1
mixture with 18A) oil; H NMR δ (para-isomer) 1.08 (d, J )
7.2 Hz, 3H), 1.19 (s, 3H), 1.25 (s, 3H), 2.98 (q, J ) 7.2 Hz,
7.13-7.31 (m, 7H), 7.44-7.52 (m, 2H). Anal. Calcd for C20H25
-
1H), 3.72 (s, 3H), 6.75 (mc, 2H), 7.13 (mc, 2H), ca. 7.21 (mc,
1
NO2S: C, 69.94; H, 7.34; N, 4.08. Found: C, 69.72; H, 7.40;
N, 4.01.
5H); H NMR δ (minor isomer, probably ortho) 1.46 (s, 3H),
1.47 (d, J ) 7.1 Hz, 3H), 1.52 (s, 3H), 2.98 (q, J ) 7.2 Hz, 1H),
3.73 (s, 3H); the aromatic signals cannot be distinguished from
those of the para isomer and those of 18A. Anal. Calcd for
Ru n 2. Chr with CH2Cl2 provided 359 mg of 11a A and 132
mg of a mixture consisting (1H NMR) of 40 mg of 11a A and
92 mg of 10A. Further elution gave 592 mg (total 684 mg,
corresponding to 75%) of 10A and a small amount of a mixture
containing (1H NMR) traces of 4, 5a , and 8. Continued elution
provided 216 mg (16%) of 7 and a small amount of a mixture
containing (1H NMR) a trace of 9A. Elution with ethyl acetate
gave 510 mg (75%) of TsNH2.
C
18H22O (mixture of 11bA and 18A): C, 84.99; H, 8,72.
Found: C, 84.98; H, 8.47.
3-Meth yl-2-(4-m eth oxyp h en yl)-2-p h en ylbu ta n e (18A):
1
oil; H NMR δ 0.81 (d, J ) 6.7 Hz, 3H), 0.83 (d, J ) 6.7 Hz,
3H), 1.57 (s, 3H), 2.65 (sept, J ) 6.7 Hz, 1H), 3.75 (s, 3H),
6.75 (mc, 2H), 7.13 (mc, 2H), ca. 7.21 (mc, Ph). Anal. Calcd
for C18H22O: C, 84.99; H, 8,72. Found: C, 85.09; H, 8.51.
Bis(m eth oxyp h en yl)m eth a n e (10A) (para-para iso-
mer): mp 51-52 °C; 1H NMR δ 3.84 (s, 2H), 3.73 (s, 6H), 6.83
(mc, 4H), 7.09 (mc, 4H), the presence of two or more isomers
in one eluate was indicated by singlets at 3.77, 3.80, and 3.91
and by a multiplet at ca. 7.13. Anal. Calcd for C15H16O2: C,
78.92; H, 7.06. Found: C, 78.79; H, 7.06.
1-P henyl-3-(4-methoxyphenyl)-2,3-dimethylbutane (11aA):
1
oil; H NMR δ 0.70 (d, J ) 6.1 Hz, 3H), 1.30 (s, 3H), 1.33 (s,
3H), 1.94 (mc, 1H), 1.95 (mc, 1H), 2.69 (mc, 1H), 3.79 (s, 3H),
6.84-6.92 (m, 2H), 6.98-7.05 (m, 2H), 7.08-7.37 (m, 5H).
Anal. Calcd for C19H24O: C, 85.03; H, 9.01. Found: C, 85.01;
H, 9.05.
Ru n 3. Chr with CH2Cl2 provided 413 mg (46%) of 11bP
and 187 mg of an inseparable mixture of isomers consisting
(1H NMR) of 125 mg (9%) of 5b and 62 mg (5%) of 17b.
Further elution yielded 39 mg (3%) of 19b and 58 mg (6%) of
9p . Elution with ethyl acetate yielded 511 mg (75%) of TsNH2.
2,3-Dip h en yl-2-m eth ylbu ta n e (11bP ): oil; 1H NMR δ 1.07
(d, J ) 7.2 Hz, 3H), 1.19 (s, 3H), 1.27 (s, 3H), 3.00 (q, J ) 7.2
Hz, 1H), 6.98-7.04 (m, 2H), 7.10-7.33 (m, 8H). Anal. Calcd
for C17H20O: C, 91.01; H, 8.99. Found: C, 90.72; H, 8.91.
N-(2,2-Dim eth yl-3-p h en yl-3-bu ten yl)tolu en e-4-su lfon a -
m id e (17b): 1H NMR δ 1.07 (s, 6H), 2.43 (s, 3H), 2.81 (d, J )
6.0 Hz, 2H), 4.68 (t br, J ) 6.0 Hz, 1H), 4.95 (d, J ) 1.1 Hz,
1H), 5.18 (d, J ) 1.1 Hz, 1H), 6.87-6.94 (m, 2H), 7.11-7.35
(m, overlapping with signals of 5b), 7.72-7.79 (m, 2H, slightly
downfield from signals of 5b). Mixture of 17b and 5b: oil.
Anal. Calcd for C19H23NO2S: C, 69.27; H, 7.04; N, 4.25.
Found: C, 69.13; H, 7.05; N, 4.17.
Rea ction of 1c in Ben zen e. Reaction and workup were
performed as described for the runs of Table 1 but without
cooling. Chr with CH2Cl2 provided 260 mg (23%) of 19c and
100 mg of a mixture consisting (1H NMR) of 69 mg (6%) of 5c
and 31 mg (3%) of 17c. Continued elution yielded 133 mg of
26 and 180 mg of a mixture consisting (1H NMR) of 125 mg
(11%) of 24 and 55 mg (total 188 mg, corresponding to 17%) of
26. Elution with ethyl acetate gave 327 mg (29%) of a mixture
of 28 and its isomer 29 in a ratio (1H NMR) of about 4:1.
N-(2,2-Dim eth yl-3-p h en yl-3-bu ten yl)ben za m id e (17c)
(in mixture with isomer 5c): oil; 1H NMR δ (17c) 1.19 (s, 6H),
3.43 (d, J ) 5.6 Hz, 2H), 5.07 (d, J ) 1.3 Hz, 1H), 5.32 (d, J )
1.3 Hz, 1H), 6.20 (s br, 1H), 7.11-7.18 (m, 2H), 7.20-7.54 (m,
6H), 7.69-7.76 (m, 2H of both isomers). Anal. Calcd for
C
19H21NO (both isomers): C, 81.68; H, 7.58; N, 5.01. Found:
C, 81.57; H, 7.40; N, 5.07.
3-(4-Meth ylp h en ylsu lfon yl)-1,1,2-tr im eth ylin d a n (19b):
3-Ben za m id o-1,1,2-tr im eth ylin d a n (19c): mp 166-169
°C; IR 3340, 1634, 1536 cm-1; 1H NMR δ 1.07 (s, 3H), 1.20 (d,
J ) 7.0 Hz, 3H), 1.35 (s, 3H), 1.92 (dq, J ) 10.0/7.0 Hz, 1H),
5.43 (t, J ) 9.9 Hz, 1H), 6.22 (d br, J ) 9.6 Hz, 1H), 7.17-7.34
(m, 4H), 7.42-7.58 (m, 3H), 7.81-7.88 (m, 2H). Anal. Calcd
for C19H21NO: C, 81.68; H, 7.58; N, 5.01. Found: C, 81.89;
H, 7.57; N, 4.80.
1
mp 104-109 °C; IR 3326, 3265, 1318, 1163 cm-1; H NMR δ
0.93 (s, 3H), 0.95 (d, J ) 7.0 Hz, 3H), 1.36 (s, 3H), 1.76 (dq, J
) 10.0/7.0 Hz, 1H), 2.46 (s, 3H), 4.40 (t, J ) 9.9 Hz, 1H), 4.60
(d br, J ) 9.6 Hz, 1H), 6.84-6.91 (m, 1H), 7.06-7.39 (m, 5H),
7.84-7.91 (m, 2H). Anal. Calcd for C19H23NO2S: C, 69.27;
H, 7.04; N, 4.25. Found: C, 69.33; H, 7.15; N, 4.12.
Ru n 4. Chr with CH2Cl2 provided 384 mg of 11bP and 72
mg of a mixture consisting (1H NMR) of 63 mg (total 447 mg,
corresponding to 50%) of 11bP and 9 mg (1.5%) of 15b.
Further elution yielded 143 mg of a mixture consisting (1H
NMR) of 56 mg of 5b and 87 mg of 17b. Continued elution
gave 183 mg of a mixture consisting (1H NMR) of 40 mg (total
96 mg, corresponding to 7%) of 5b, 45 mg (total 132 mg,
corresponding to 10%) of 17b, and 98 mg of 19b. Further
elution provided 26 mg (total 124 mg, corresponding to 9%) of
19b and 57 mg (5%) of 9P . Elution with ethyl acetate gave
451 mg (66%) of TsNH2.
1-Ben zoyl-2,2,3-tr im eth yl-3-p h en yla zetid in e (28) (con-
1
taminated with isomer 29): viscous mass; IR 1656 cm-1; H
NMR δ 1.28 (s, 3H), 1.62 (s, 3H), 1.80 (s, 3H), 3.88 (d, J ) 8.4
Hz, 1H), 4.65 (d, J ) 8.4 Hz, 1H), 7.01-7.52 (m, 8H), 7.60 (mc,
2H); MS (28, 138 °C) m/e (relative intensity) 279 (2, M+), 162
(14), 118 (100), 105 (45), 77 (26). Anal. Calcd for C19H21NO:
C, 81.68; H, 7.68; N, 5.01. Found: C, 81.59; H, 7.98; N, 4.96.
Molecular mass calcd for M+ of C19H21NO: m/e 279.1624, found
m/e 279.1625.
1-Ben zoyl-2,3,3-tr im eth yl-2-p h en yla zetid in e (29) (only
in mixture with main component 28): 1H NMR δ 0.89 (s, 3H),
1.26 (s, 3H), 1.62 (s, 3H), 3.85 (mc, 1H), 4.60 (mc, 1H), 7.01-
7.62 (m, indistinguishable from 28).
Ru n 5. Chr with CH2Cl2 provided 317 mg of a mixture
consisting (1H NMR) of a trace of 15b, 118 mg (12%) of 11bA,
and 199 mg of its isomer 18A. Further elution yielded 428
mg (total 627 mg, corresponding to 62%) of 18A and 255 mg
of 10A (para-para-10A containing an isomer) and 510 mg of
10A (para-para only, total for all isomers 765 mg, correspond-
ing to 86%). Elution with ethyl acetate gave 683 mg (100%)
of TsNH2.
Ack n ow led gm en t. This work was supported by the
Fonds der Chemischen Industrie.
J O980774M