ライフサイエンスコーパス: carbenium

1 F/SbF5 through a superelectrophilic ammonium-carbenium activation process.

2 ium ylides 1(a-d) with several pi-conjugated carbenium and iminium ions have been investigated.

3 SO2 and makes a normally unreactive tertiary carbenium carbon susceptible to addition.

4 miliar trend based on electron demand at the carbenium center.

5 The 1,3-dimethylcyclopentenyl carbenium ion (C7H11(+)) was reproducibly prepared on ze

6 rly transfer its hydride to the intermediate carbenium ion (stabilized in the form of a cationic thio

7 Bridged fluoronium ion 1, carbenium ion 2, and fluorocarbenium ion 3 were found to

8 dition sites (X-CH=CH2; X = CHO, NO2), eight carbenium ion acceptors, fulvene, borane, and SiH3(+) we

9 h, upon activation, dissociates generating a carbenium ion and dihydrocinnamic acid, or rearranges to

10 ectrophilic and extremely reactive secondary carbenium ion can be isolated in a neutral, nucleophilic

11 lecular attack of tetracoordinate carbons on carbenium ion centers were located; in some cases, such

12 e formation of the energetically most stable carbenium ion conformation, followed by the cyclization

13 evidence of the intervention of a secondary carbenium ion in the reaction path.

14 The reaction likely involves an allyl carbenium ion intermediate in which the adjacent stereoc

15 that: (1) the reaction proceeds via a cyclic carbenium ion intermediate, (2) the relief of strain in

16 azole phosphate fragments, consistent with a carbenium ion intermediate.

17 The resulting carbenium ion is likely to be further stabilized by prot

18 , where cyclization of the indole-stabilized carbenium ion is slower.

19 tensions of our recently developed theory of carbenium ion stability in zeolites.

20 obile pentene phase and in production of the carbenium ion that reacts with the mobile pentene.

21 r loading, a proton was transferred from the carbenium ion to the base to leave 1,3-dimethylcyclopent

22 C bond followed by trapping of the resultant carbenium ion with boron-bound hydride.

23 (PA = 188 kcal/mol) does not deprotonate the carbenium ion, but these species do react as nucleophile

24 at the reactive electrophile, the cyclohexyl carbenium ion, is directly formed in a protonation step

25 dimers dehydrate without the formation of a carbenium ion, which would otherwise have contributed to

26 lication of related clock reactions in other carbenium ion-based branches of organic synthesis is con

27 dged, dicationic, protonated tetrahydrofuran-carbenium ion.

28 rption of cyclohexene and the formation of a carbenium ion.

29 ts of the reaction originate from a tertiary carbenium ion.

30 lefin and the transfer of the hydride to the carbenium ion.

31 mpurities that might serve as initiators for carbenium-ion mechanisms, and the active catalyst was fr

32 vation barrier to form an alkoxy group via a carbenium-ion transition state.

33 Elimination involves E1 pathways and late carbenium-ion transition states.

34 f the alkene-like organic moiety at the late carbenium-ion-type transition states involved.

35 The relative reactivity of carbenium ions (methyl > ethyl > iso-propyl > tert-butyl

36 uted carbenes (X-CH, singlets and triplets), carbenium ions (X-CH2(+)), and their hydrogen addition p

37 philic addition of SO2, SO2ClF, and SO2F2 to carbenium ions and the nucleophilic addition of SO2 to 1

38 miniscent of the degenerate rearrangement of carbenium ions formed upon protonation of olefins.

39 oretical data for the addition of solvent to carbenium ions uniformly agree with experiments by Olah

40 emperature via hydride extraction to produce carbenium ions, (b) alkylate benzene without a Friedel-C

41 The carbenium ions, borane, and SiH3(+) gave not transition

42 DeltaH(ACID); hydride ion affinities of the carbenium ions, HIA; and enthalpies of hydrogenation of

43 r of stabilized aryl or heteroaryl(3-indolyl)carbenium ions, never previously prepared in the solid s

44 of cyclization and reduction of intermediate carbenium ions, where cyclization of the indole-stabiliz

45 through transition states much like primary carbenium (nitrenium, oxenium) cations, poorly conjugate

46 und is prepared in three steps from a simple carbenium precursor.

47 on centers were located; in some cases, such carbenium-to-carbonium rearrangement processes (in which