2210
J. K. WILLIAMS,D. W. WILEYAND B. C. MCKUSICK
Presumed Ethyl 2-Acetoxymercuri-2-deoxy3,4,6-tri-Oacetyl-,%D-glucoside (IIIa).-A filtered solution of 6.4 g. (0.02 mole) of mercuric acetate (Mallinckrodt, anal. reag.) in 100 ml. of anhydr. ethanol was added to a solution of 5.45 g. (0.02 mole) of n-glucal 3,4,6-triacetate in the same solvent. Formation of white needles was observed within 5 min. at room temp., after which the reaction mixture was refrigerated for 2 hr. A first crop (4 9.) was collected, washed with cold isopropyl alcohol and then 30-60" petroleum ether. A second crop (1.2 g.) was obtained by concentrating combined filtrate and washings to 50 ml., adding 30 ml. of 30-60" petroleum ether and refrigerating for 1 hr. Three recrystallizations of the combined crops from isopropyl alcohol provided 4.5 g. (3970) of white crystals melting at 172-173.5'. The infrared spectrum of this compound is very similar to that of 111. Anal.Z8 Calcd. for C16HzrOloHg: C, 33.30; H , 4.19; Hg, 34.77; EtO, 7.81. Found: C, 33.43; H, 4.41; Hg, 34.65; EtO, 7.70. Presumed Ethyl 2-Chloromercuri-2-deoxy-3,4,6-tri-O-acetyl-,%D-glucOside (ma).-A solution of 2.9 g. (0.005 mole) of I I I a in 50 mi. of 95% ethanol was treated with 5 ml. of satd. aq. NaC1. After 2 hr. a t rm. temp. and overnight refrigeration, 1.25 g. of white crystals melting a t 138-144' was collected. Evaporation to dryness of the filtrate, ex-
[CONTRIBUTION No. 658 FROM
THE
Vol. 84
traction of the resulting residue with CHClr, evaporation to dryness of the extract and recrystallization from isopropyl alcohol-30-60' petroleum ether of the remaining solid provided 1.15 g. of crystals melting a t 139-145'. The combined crops were recrystallized three times from isopropyl alcohol-petroleum ether to yield 2.0 g. of long, fine, white needles melting a t 146-147' and with an infrared spectrum very similar to that of IV. Ana1.27 Calcd. for C1,H81O8: HgCl: C, 30.38; H, 3.82; Hg, 36.25; EtO, 8.14. Found: C, 30.57; H , 4.02, Hg, 36.40; EtO, 8.21. Presumed Isopropyl 2-Acetoxymercuri-2-deoxy-3,4,6-tri0-acetyl-fl-D-glucoside IIIb .-The procedure was the same as for the preparation of I I I a except that isopropyl alcohol (Baker, anal. reag.) was used in place of ethanol. Two recrystallizations from isopropyl alcohol-30-60" petroleum eth5r provided a 4Oy0yield of white needles melting a t 190191 . The infrared spectrum of IIIb is similar to those of I11 and IIIa. Anal.27 Calcd. for C17H26010Hg: C, 34.55; H, 4.43; Hg, 33.94. Found: C, 34.70; H , 4.63; Hg, 33.76. Infrared spectra were obtained on Nujol mulls with a model 21C Perkin-Elmer spectrophotometer. Melting points were determined in a Thomas-Hoover apparatus and are not corrected.
CENTRAL RESEARCH DEPARTMENT, EXPERIMENTAL STATION, E. I. DU PONT DE NEMOURS AND Co., WILMINGTON 98, DEL.]
Cyanocarbon Chemistry. XIX.1#2 Tetracyanocyclobutanes from Tetracyanoethylene and Electron-rich Alkenes BY J. K. WILLIAMS,D. W. WILEYAND E. C. MCKUSICK RECEIVED NOVEMBER 13, 1961
1,1,2,2-Tetracyanocyclobutanes are formed in high yield under very mild reaction conditions by the cycloaddition of tetracyanoethylene to electron-rich alkenes such as methyl vinyl ether and p-methoxystyrene. 1,1,2-Tricyanocyclobutanesa r e formed similarly from tricyanoethylene.
The thermal addition of allenes, fluoroalkenes and ketenes to alkenes to give cyclobutanes has been extensively investigated in the last few years I and is nom one of the most important routes to cyclobutanes, some of which are useful as pre- X = RO-,R S , R(R'C0)N-, CsH6SOzN(R)-, P-ROCsHs cursors of alicyclic corn pound^.^^^ Tetracyanoethylene, a reactive dienophile in the Diels-Alder other acyclic products via ring-opening reactions. In striking contrast to cycloaddition reactions of r e a ~ t i o n has , ~ been observed to form cyclobutane derivatives with a few 1,3-diene systems to which allenes, fluoroalkenes and ketenes, which require several hours of heating a t 100-225', the cycloDiels-Alder addition is difficult or impossible.s It has now been found that tetracyanoethylene addition reactions of tetracyanoethylene generally The readily forms 1,1,2,2-tetracyanocyclobutanes (I) occur rapidly and in high yield a t 0-30'. with a variety of electron-rich alkenes.' Tricyano- reactions are easy to follow because tetracyanoethylene behaves similarly. As will be described ethylene forms highly colored 7-complexes with in a subsequent paper, these polycyanocyclobutanes alkeness; when the color fades, the cycloaddition are good sources of 1,1,2-tricyanobutadienes and reaction is over. Thus, addition of methyl vinyl ether to a tetrahydrofuran solution of tetracyano(1) Paper XVIII, J. R . Roland and B. C. McKusick, J . A m . Chem. ethylene a t room temperature caused the solution SOC.,8 3 , 1652 (1961). to become deep orange; heat was evolved, the (2) Presented at the St. Louis Meeting of the American Chemical orange color faded to pale green in the course of Society, March, 1961. (3) J. D.Roberts and C. M. Sharts, "Cyclobutane Derivatives from half an hour, and 1,1,2,2-tetracyano-3-methoxyThermal Cycloaddition Reactions" in "Organic Reactions," John cyclobutane was isolated as a colorless solid in 90% Wilry and Suns, Tnc., in press. yield. (4) Recently, the thermal reaction of isobutenylamines with electroVinyl ethers, vinyl sulfides, N-vinylamides and philic olefins such as methyl acrylate and diethyl maleate has been reported to give cyclobutanes; K. C . Brannock, A. Bell, R. D. Burpitt N-vinylsulfonamides all form tetracyanocycloand C . A. Kelly, J . Ore. Chcm., 2 6 , 625 (1961). butanes with tetracyanoethylene as illustrated in (5) W. J. Middleton, R. E. Heckert, E. L. Little and C. G.Krrspan, Table I. The vinyl group can be substituted; J . A m . Chem. SOC.,80, 2783 (1958). thus, dihydropyran gives a bicyclic adduct (11), (6) A. T. Blomquist and Y. C. Meinwald, ibid., 81, 667 (1959); J. K. Williams, i b i d . , 81, 4013 (1959); D.S.Matteson, J. J. Dtysdale as does the 1,2-dialkoxyethylene 2,2-dimethyland W. H. Sharkcy, ibid., 82,2853 (1960); K.Hafner and J. Schneider, dioxole, and 4-methylenedioxolane forms a spiro Ann., 624, 37 (1959). (7) We are greatly indebted to Prof. Saul Winstein of the University of California et Lo8 A n d e s for first suggesting this reaction.
(8) R. E. Merrifield and W. D. Phillips, J . A m . Chem. SOC.,80,2778 (1968).
2211
FORMATION OF TETRACYANOCYCLOBUTANES
June 5, 1962
TABLE I 1,1,2,%TBTRACYANOCYCLOBUTANES
PROPERTIES OF
Yield,
%
%-
-Carbon, Calcd.
M.p., OC.
X -Hydrogen, %Calcd. Pound
Found
%-
--Nitrogen, Calcd.
Found
90 82 83 77
158-159. 5d 140-141d 148- 150d 105-106d
58.1 59.7 68.7 51.2
58.1 59.8 68.6 51.1
3.3 4.5 3.8 3.0
3.3 4.0 3.8 3.1
30.1 27.9 21.4 23.9
30.0 27.8 21.3 23.9
90
130-130.5"
60.3
60.5
3.8
3.9
29.3
29.5
91 83
130-145 d.' 55.4 54.7 3.4 3.3 119.5-121' 64.7 65.0 3.6 3.2 20.1 20.4 123-124.5' 5 Recrystallization was conducted a t room temperature by diluting an acetonitrile solution of the cyclobutane with ether. The product was unstable; the analytical sample darkened at room temperature even when protected from the atmosphere The two isomorphs had essentially the same infrared spectra c Crystallized from a 1,2-dichloroethane-cyclohexane mixture. in Nujol mulls. They were interconvertible by appropriate seeding. The higher melting form crystallized as cubes; Recrystallized from 1,2-dichloroethane. e Mol. wt. the lower melting form crystallized as needles and was analyzed. calcd. 201, found 201.
*r+z
TABLE I1 PROPERTIES OF 1,1,2,2-TETRACYANO-3-ARYLCYCLOBUTAXES
Yield,
P-CHaOCoHI-
H
H
Yo 93
P-CHaOCsHr
H
-CHa
85
135-13eb
P-CHaOCsHr
CH,
H
69
148-150"
P-CH80&4-
CH3
CHI
45
131-133b
. \; L o u
H
CHI
100
199.5-200d
Ar
RI
\
R,
M.p., "C.
182-183"
CHsCN Xrnsr, mr ( e )
238(13,000) 272 (1,630) 282 (1,210) 239(13,600) 272 (1,640) 282 (1,190) 232(10,700) 277 (1,530) 283 (1,240) 232(10,900) 277 (1,420) 283 (1,190)
RZ
(Ch')?
-Carbon, %Calcd. Found
Hydrogen, % Calcd. Found
-Nitrogen, %Calcd. Found
68.7
68.6
3.9
3.9
21.4
21.5
69.6
69.7
4.4
4.5
20.3
20.9
69.6
69.7
4.4
4.5
70.3
70.5
4.9
5.1
66.2
66.1
3.5
3.7
19.3
19.2
4.4 20.3 20.0 O-CHaOCsHdCHs H 63 162-162.5' 69.6 69.7 4.4 Recrystallized from benzene. e Recrystallized from methyl ethyl ketone5 Recrystallized from 1,2-dichloroethane. methanol, Recrystallized from 1,2-dichloroethane-cyclohexane. Recrystallized from 1.2-di~hloroethane-ether~
*
The electron-donating group need not be atadduct (111). However, with l-methoxy-1,3-butadiene, tetracyanoethylene reacts to give the Diels- tached directly to the double bond undergoing cycloaddition. Its effect may be transmitted Alder adduct 1,1,2,2-tetracyano-3-methoxy-4-cyclohexene (IV). These results and the fact that through a benzene ring, as is illustrated by the ad4,5-dimethylenedioxolane also forms a Diels- ducts with alkoxystyrenes listed in Table 11. Alder adduct (V) with tetra~yanoethylene,~ indi- Compound VI, having a double bond hindered by cate that Diels-Alder addition of tetracyanoCN C S ethylene is favored over cycloaddition when both ,CH3 I 1 are possible. X-CH=CH-C-C-H
mc";;:
(CN)Z
0
(CN2
I1
6ZN)* (CNh
I11
Found: C,59.4; H,4.6; N,26.1. Reaction of Tetracyanoethylene with Styrene.-A mix- three examples. The n.m.r. spectrum of the anethole adduct (A = CHs, Zure of 2.56 g. (0.02 mole) of tetracyanoethylene, 5.20 g. (0.05 mole) of styrene and 10 ml. of xylene was heated a t B = p-anisyl) is interpreted to consist of aromatic H a t reflux for 4 hours. The black mixture was then mixed with 2.70, CHsO a t 6.18 and CHI (doublet) a t 8.43 T . The rest 150 ml. of petroleum ether (30-60') with stirring. The of the spectrum consists of an AB-type quartet with the black solid that formed was separated by filtration to give components of the doublet associated with H1 proton x pale yellow filtrate. Concentration of the filtrate gave being split into quartets by the methyl group. The fine an orange oil. This oil was dissolved in 5 ml. of hot cyclo- structure of these quartets was partially obscurred by the hexane and cooled to give 0.46 g. of almost colorless needles, OCHa absorption but could be seen clearly in the related m.p. 75-80'. Recrystallization from cyclohexane and iso-safrole adduct (where A = CHI, sublimation gave a white solid, m.p. 85-86', identified by mixed m.p. and infrared spectrum as benzalmalononitrile. The dried black solid above was mixed with 30 g. of alumina and added to the top of an alumina column (90 g., acid Woelm, Activity I ) constructed in benzene. The The coupling constants are approximate. column was developed with 1: 1 benzene-ethylene chloride. (21) S. Widequist, ArRiu. Kemi. Mineral Gcol., 2OB, No. 4, 8 A total of 1500 ml. of solution was required to move a yellow band off the column while a dark brown band had (1945). moved two-thirds of the way down the column. Further (22) J. A. Pople, W. G.Schneider and H J. Bernstein, "High Resodevelopment of the column gave only tarry residue. Con- lution Nuclear Magnetic Resonance," McGraw-Hill Book Co.,I n c . , centration of the initial 1500 ml. of yellow solution afforded New York, N. Y.,1959, p p . 132-138.
