Ketenes. IV. Reactions of Ketenes with Ketene O,N-Acetals and Ketene N,N-Acetals<sup>1</sup>

Hasek, Robert H.; Gott, P. Glenn; Martin, J. C.

doi:10.1021/jo01032a007

Cited by 23 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The electronic nature of the R group has no apparent impact on the product yield under these conditions ( Table 1, entries [6][7][8][9][10][11][12][13][14][15][16]. When the R group increases the electrophilicity of a benzoyl chloride, it simultaneously decreases the nucleophilicity of the diacyl ketene-N,N¢-acetal intermediate, and vice versa.…”

mentioning

confidence: 99%

Tandem Reactions of 2-Methylimidazoline and 1,2-Dimethylimidazoline with Various Benzoyl Chlorides

Ye¹,

Chen²,

Chatterjee³

et al. 2009

Synthesis

View full text Add to dashboard Cite

The reactions of 2-methylimidazoline with excess benzoyl chlorides under mild conditions generated N,N¢-diacyl-b-keto cyclic ketene-N,N¢-acetals. Conversely, the corresponding reactions of 1,2-dimethylimidazoline under the same conditions stereoselectively formed the ring-opened (Z)-vinyl benzoates. The latter reactions feature the formation of carbon-carbon bonds, carbonnitrogen bonds, and carbon-oxygen bonds in one sequential cascade.

show abstract

mentioning

confidence: 99%

Tandem Reactions of 2-Methylimidazoline and 1,2-Dimethylimidazoline with Various Benzoyl Chlorides

Ye¹,

Chen²,

Chatterjee³

et al. 2009

Synthesis

View full text Add to dashboard Cite

show abstract

“…Distance from the middle of the doublets to the middle of the triplet = 20.8 Hz; CCI3F as external standard.CH30H, 48 h at 20 "C) were concentrated and analyzed gaschromatographically (for yields see Table 1); the bicyclo-t4.2.21decatetraene derivatives (6) and (8) were separated by preparative gas chromatography. Product (7) was obtained by distillation of the concentrated pentane extract from the rearrangement mixture of ( 4 ) (in CH30H. 40 h a t 20°C) and was obtained pure (m.p.…”

mentioning

confidence: 99%

Cyclobutanones from Enamines and Ketenes by Two‐stage Addition

Otto¹,

Feiler²,

Huisgen³

1968

Angew. Chem. Int. Ed. Engl.

View full text Add to dashboard Cite

8) U (8)O (3),(4), R = Br (4),(7), kl = COOCH3 Table I . Rearrangements of the monosubstituted bullvalenes ( 3 ) -( 5 ) . 254 (3600) 263 (3680) 272 (2900) sh ~ 256 (3340) 265 (3270) 276 (2240) sh --. -4.3, m; i 7 : 5.0, pseudoquartet, (together 7H); T = 6.8 (2H), broad m [el 257 (3380) 266 (3320) 278 (2320)sh 257 (3600) 266 ,(3660) 275 (2260) sh IH-NMR [bl i = 4.1 (SH), complex multiplet; T -~ 4.6 (ZH), symm. 4-line signal [dl; c = 6.6 (lH), m; 7 = 6.9 (lH), m r 7 3.3 (lH), d (J = 6.5 Hz): r = 4.2 (6H), m; c = 6.2, m; 7 7 6.33 (together 4H), s; i = 6.7 (IH), pseudoquartett ( J = 6.5 Hz) 7 == 4.3 (SH), m; i i 6.8 (lH), m [a] In cyclohexane [bl Varian A 56/60 A; CC14 solution; TMS as internal standard. [cl Determined by gas chromatography. Id] Since this signal, due to the protons of the ethylene bridge 111, corresponds to only 2 H, the Br must be on the ethylene bridge. [el 19F-NMR: S :=-i 9 9 . 2 pprn (J = 4.8 Hz), pseudodoublet; S = -t-99.5 ppm ( J = 4.8 Hz), pseudotriplet; S = +99.8 ppm ( J = 4.8 Hz), pseudodoublet. Distance from the middle of the doublets to the middle of the triplet = 20.8 Hz; CCI3F as external standard.CH30H, 48 h at 20 "C) were concentrated and analyzed gaschromatographically (for yields see Table 1); the bicyclo-t4.2.21decatetraene derivatives (6) and (8) were separated by preparative gas chromatography. Product (7) was obtained by distillation of the concentrated pentane extract from the rearrangement mixture of ( 4 ) (in CH30H. 40 h a t 20°C) and was obtained pure (m.p. 45 to 45.5 "C) by recrystallization. Compounds (5)-(8) were characterized by their spectra (UV, IR, NMR). It is not possible t o tell from the results so far available to which of the three possible positions the olefinic fluorine atom of ( 8 ) o is attached. The heavy-metal salts are probably involved in the reaction more as complex-formers [81 than as Lewis acids. Bullvalene (2) in ether is unaffected by boron trifluoride-ether even after long contact times. ranges to cis-9,lO-dihydronaphthalene after longer reaction times.[4] We thank Professor M . Jones, Jr., for placing the IR spectrum of (1) at our disposal. [ 5 ] o b , o c nomenclature, see J. F. M . Oth, R. Merenyi, J . Nielsen, and G. Schroder, Chem. Ber. 98, 3385 (1965). B = substituent attached to bridgehead; 0 = substituent attached to an olefinic C atom ( 0 , nearer to the cyclopropane ring, o b nearer to the bridgehead). I cis-Stereospecificity 11-31 and solvent-dependence of the addition constants [41 provide strong evidence that cycloadditions of ketenes to olefins and vinyl ethers are one-stage multicenter reactions. Exclusive formation of cyclobutanones (and not Diels-Alder adducts) from ketenes and 1,3-dienes points in the same direction [51. Enamines appear, however, to react by a different mechanism, at least in polar solvents. Here apparently a two-stage process involving a zwitterion [seeAfter treatment of dimethylketene ( I ) with l-isobutenylpiperidine (2b) or N,N-dimethylisobutenylamine in polar solvents, Hnsek and Martin [61 isolated the cyclobu...

show abstract

“…For l-isobutenylpiperidine the ratios ( 3 6 ) :(4b) by procedures (1) and (2) were 2.4:l and 0.96:1, respectively; and for 4-isobutenylmorpholine ( 2 c ) the corresponding ratios ( 3 c ) : (4e) were 4 S : l and 2.2:1, respectively. We obtained the cyclobutanone (10) as main product of the reaction of diphenylketene (7) with (Zc) in n-pentane at + 5 "C if traces of acid were removed by addition of potassium carbonate. Boiling with methanol, or addition of acid even in the cold, rearranged (10) to the cis-trans-isomers ( 9 A ) and (98) of the 2-tetralone.…”

mentioning

confidence: 99%

A Spirocyclic 1:2 Adduct of Tetrakis(diphenyl‐arsorylmethyl)methane and Hydrogen Peroxide

Ellermann

Schirmacher

1968

Angew. Chem. Int. Ed. Engl.

View full text Add to dashboard Cite

d(4j /d (5) = kl/k2(dimethylketene) rapidly occur after the rate-determining step, namely the formation of ( 3 ) from ( I ) and (2).The following experiments (1) and (2) prove the dependence of the ratio (4):(5) on the concentration of ( I ) and on the mode of addition. (1) If 11.9 mmoles of dimethylketene ( I ) in 15 ml of acetonitrile were added to a solution of 42.6 mmole of I-isobutenylpyrrolidine ( 2 a ) in 35 ml of acetonitrile during 30 min at 20 "C, then dimethyketene (1) was consumed so rapidly that the solution became merely pale yellow; distillation in a high vacuum gave 5.7 mmoles of 1 : 1 adduct (4a) and 0.34 mmole of 2: 1 adduct (Sa), i.e., a ratio of 17: 1.(2) However, when 2.6 mmoles of (2a) were added all at once to 11.9 mmoles of ( I ) in 15 ml of acetonitrile, then the yellow ketene solution was decolorized only after 10 h; the excess of (1) was converted into the dimer (6); working-up in this case yielded 1.26 mmoles of ( 4 a ) and 0.87 mmole of ( S a ) , i.e. a ratio of only 1.4:l.

show abstract

Ketenes. IV. Reactions of Ketenes with Ketene O,N-Acetals and Ketene N,N-Acetals¹

Cited by 23 publications

References 0 publications

Tandem Reactions of 2-Methylimidazoline and 1,2-Dimethylimidazoline with Various Benzoyl Chlorides

Tandem Reactions of 2-Methylimidazoline and 1,2-Dimethylimidazoline with Various Benzoyl Chlorides

Cyclobutanones from Enamines and Ketenes by Two‐stage Addition

A Spirocyclic 1:2 Adduct of Tetrakis(diphenyl‐arsorylmethyl)methane and Hydrogen Peroxide

Contact Info

Product

Resources

About

Ketenes. IV. Reactions of Ketenes with Ketene O,N-Acetals and Ketene N,N-Acetals1

Cited by 23 publications

References 0 publications

Tandem Reactions of 2-Methylimidazoline and 1,2-Dimethylimidazoline with Various Benzoyl Chlorides

Tandem Reactions of 2-Methylimidazoline and 1,2-Dimethylimidazoline with Various Benzoyl Chlorides

Cyclobutanones from Enamines and Ketenes by Two‐stage Addition

A Spirocyclic 1:2 Adduct of Tetrakis(diphenyl‐arsorylmethyl)methane and Hydrogen Peroxide

Contact Info

Product

Resources

About

Ketenes. IV. Reactions of Ketenes with Ketene O,N-Acetals and Ketene N,N-Acetals¹