ライフサイエンスコーパス: electrocyclic

1 e synthesized and employed for light-induced electrocyclic 4pi ring closure leading to bicyclo-beta-l

2 ated (large) differences in barriers between electrocyclic and sigmatropic pathways.

3 emperature, the allenyl compounds undergo an electrocyclic cascade to give bicyclo[4.2.0]octadienyl-f

4 proceeds to the major product by sequential electrocyclic closure and a 1,2-shift, rather than the e

5 Along a competitive pathway, electrocyclic closure to an isophenanthrene is predicted

6 The orbital symmetry forbidden thermal electrocyclic equilibria between a series of cyclophaned

7 Torquoselectivity in the electrocyclic interconversions of 1-azapolyenes and thei

8 thienylimidazolium salt was found to undergo electrocyclic isomerization upon exposure to UV radiatio

9 synthesized and found to undergo reversible electrocyclic isomerization upon successive exposure to

10 ally a transition state in their stress-free electrocyclic isomerization.

11 anion that cyclizes either by a suprafacial electrocyclic mechanism, or through a kinetically contro

12 An electrocyclic pathway via an electrocyclic ring opening

13 rationalized in terms of a Nazarov-type 4pi-electrocyclic reaction followed by pi-cyclization onto t

14 The semiquinone species undergo a type of electrocyclic reaction known as a 1,5-sigmatropic shift

15 enyl is more likely the result of a distinct electrocyclic reaction than quenching of a two-step mech

16 nd the first step of the mechanism, and both electrocyclic reactions are favored by coordination to t

17 Drafts of the Stereochemistry of Electrocyclic Reactions paper and letters and notes by W

18 dward-Hoffmann paper, The Stereochemistry of Electrocyclic Reactions, ushered into organic chemistry

19 o explain and predict the stereochemistry of electrocyclic reactions.

20 and the origin of torquoselectivity in these electrocyclic reactions.

21 he 6-31G* basis set, was used to examine six electrocyclic rearrangements, each involving a 1,2,4,6-h

22 ing experiments show that 4 does not undergo electrocyclic ring closure but reacts exclusively by pho

23 rmation of the enamine is such that a facile electrocyclic ring closure is ensured, which is corrobor

24 An electrocyclic ring closure is the key step of an efficie

25 The electrocyclic ring closure occurs in the singlet excited

26 t that a highly stereoselective 6pi-electron electrocyclic ring closure of 1-azatrienes is a key step

27 he first highly stereoselective 6pi-electron electrocyclic ring closure of 1-azatrienes.

28 An electrocyclic ring closure of a 2-azapentadienyl anion g

29 alculations on the potential surface for the electrocyclic ring closure of E-7-azahepta-1,2,4,6-tetra

30 quinone unit by an extremely facile oxa-6pi-electrocyclic ring closure reaction of an ortho-quinone

31 8 can be explained in terms of photoinduced electrocyclic ring closure resulting in the formation of

32 onosubstituted tetraenes readily undergo 8pi electrocyclic ring closure to form 1,3,5-cyclooctatriene

33 e substituent, the enamines undergo a facile electrocyclic ring closure to form a cyclohexadiene, whi

34 s to give the photoaddition product; and (3) electrocyclic ring closure to give benzoxanthene derivat

35 went either reverse proton transfer (RPT) or electrocyclic ring closure to give dihydrobenzoxanthenes

36 ion to give a QM that underwent quantitative electrocyclic ring closure to give the corresponding ben

37 , PhCH2CO2(-), PhO(-)) undergo photochemical electrocyclic ring closure to produce a zwitterionic int

38 n situ with multiple nucleophiles or undergo electrocyclic ring closure to yield hydroxynaphthalenes

39 involves an E-Z alkene isomerization, a 6pi electrocyclic ring closure, a [1,5]-sigmatropic shift of

40 for rotation around the exocyclic C==N bond, electrocyclic ring closure, and loss of N(2) were calcul

41 ) reveal that in the transition state of 4pi electrocyclic ring closure, the oxazolidinone ring and t

42 hiazole undergoes phototransposition via the electrocyclic ring closure-heteroatom migration pathway

43 ism, elimination of acetic acid, and a final electrocyclic ring closure.

44 thermochemistry and transition states of the electrocyclic ring closures of the resonance-stabilized

45 ese azaelectrocyclizations, we modeled these electrocyclic ring closures using the M06-2X density fun

46 f a formal [2 + 2]-cycloaddition followed by electrocyclic ring opening and a terminating [4 + 2]-typ

47 -1,2,4,6-tetraen-1,7-dione (17a) by means of electrocyclic ring opening followed by a facile 1,5-H sh

48 An electrocyclic pathway via an electrocyclic ring opening followed by a ring flip and a

49 nzocyclobutene undergo an ultrasound-induced electrocyclic ring opening in a formally conrotatory and

50 rtion, and aromatic C-C double bond addition/electrocyclic ring opening obey saturation (Michaelis-Me

51 Electrocyclic ring opening of 4,6-fused cyclobutenamides

52 ence of N-methylation, cyanide addition, and electrocyclic ring opening of a 4-oxazoline intermediate

53 N(-) to produce the azomethine ylide 24b via electrocyclic ring opening of an oxazoline 23b.

54 s that the force-induced acceleration of the electrocyclic ring opening of gem-dichlorocyclopropanes

55 ep process involves three cycloadditions and electrocyclic ring opening of the strained Dewar anthrac

56 rmediates (perhaps the result of 10-electron electrocyclic ring opening of the tetraene 8), synthetic

57 ding through formal [2+2] cycloaddition, 4pi-electrocyclic ring opening, and 6pi-electrocyclic ring-c

58 de reaction involving a Michael addition-6pi-electrocyclic ring opening-proton transfer and 6pi elect

59 igmatropic hydrogen shift and a two-electron electrocyclic ring opening.

60 ion, 4pi-electrocyclic ring opening, and 6pi-electrocyclic ring-closing events, constitutes a robust

61 , electrocyclic ring-opening of cyclobutene, electrocyclic ring-closing of Z-hexatriene, the [1,5]-H

62 l condensation and a reversible 6pi-electron electrocyclic ring-closure of 1-oxatrienes.

63 d mechanism of a 4pi-conrotatory Mobius-type electrocyclic ring-closure reaction.

64 s of diynes and aldehydes afforded the [3,3] electrocyclic ring-opened tautomers, rather than pyrans,

65 e two possibilities, an allowed six-electron electrocyclic ring-opening is predicted to be highly fav

66 er cycloaddition of butadiene with ethylene, electrocyclic ring-opening of cyclobutene, electrocyclic

67 e pericyclic transition state (15TS) for the electrocyclic ring-opening of oxetene (15) to acrolein (

68 teps in the evolution of this system are the electrocyclic ring-opening of the 2H-pyran to a alpha-me

69 xide systems show that the thermally allowed electrocyclic ring-opening pathway is favored by less th

70 The ultrafast light-activated electrocyclic ring-opening reaction of 1,3-cyclohexadien

71 at both processes may occur by a 10-electron electrocyclic ring-opening reaction of eta(2)-organocoba

72 are used to study the stereochemistry of the electrocyclic ring-opening reaction of the cyclopropyl r

73 changes colour as it undergoes a reversible electrocyclic ring-opening reaction under tensile stress

74 eaction energetics and transition states for electrocyclic ring-opening reactions of 3-silyl, fluoros

75 rts of inward torquoselectivities in thermal electrocyclic ring-opening reactions of 3-silylcyclobute

76 Transition structures for the conrotatory electrocyclic ring-opening reactions of N-substituted 2-

77 to proceed through a mechanism involving an electrocyclic ring-opening step.

78 oxetenes are formed and subsequently undergo electrocyclic ring-opening to methyl vinylketones.

79 e product: (1) thermally allowed conrotatory electrocyclic ring-opening, (2) thermally forbidden disr

80 a [1,5]-sigmatropic shift of hydrogen, a 6pi electrocyclic ring-opening, and a Diels-Alder cycloaddit

81 ce for a pathway that avoids metal-templated electrocyclic ring-opening, but the pericyclic pathway i

82 opening, (2) thermally forbidden disrotatory electrocyclic ring-opening, or (3) nonpericyclic C-C bon

83 earranges to 1,2-dimethylenecyclopentane via electrocyclic ring-opening.

84 Key transformation involves an oxa-6pi electrocyclic ring-opening/hetero-Diels-Alder pericyclic

85 e to 12-annulenes, sigmatropic 1,5-H-shifts, electrocyclic ring-openings of the 6-membered rings, and

86 The free-energy barrier for this electrocyclic route was shown to be very close to the bi