コーパス検索結果 (１語後でソート)
通し番号をクリックするとPubMedの該当ページを表示します
1 beta-anomers 1 and 2 and their corresponding oxocarbenium 3, coupled with relaxed potential energy su
3 shown to catalyze both Mukaiyama-Mannich and oxocarbenium aldol reactions with high efficiency and en
4 tal formation coupled with a selective axial oxocarbenium allylation allowed for the preparation of t
5 carbonyl compounds are resonance hybrids of oxocarbenium and carboxonium ions, while the latter are
6 stereoselective reduction of the appropriate oxocarbenium cation and a highly chemo- and diastereosel
9 tive axial reduction of an in situ generated oxocarbenium cation to assemble the beta-C-glycoside moi
10 tereoselective reductions of the appropriate oxocarbenium cations that were derived from a common del
11 bond of inosine by nucleoside hydrolase has oxocarbenium character and a protonated leaving group hy
14 n followed by oxidation to form a 5-membered oxocarbenium intermediate and subsequent nucleophilic ri
15 proposed by M. D. Erion et al., in which an oxocarbenium intermediate is stabilized by phosphate and
17 amide combination promotes the generation of oxocarbenium intermediates from acetal substrates at low
18 tent with a mechanism involving formation of oxocarbenium intermediates or transition states during t
19 sumably via the in situ formation of alkenyl-oxocarbenium intermediates, which eliminates the need fo
23 n this scenario, both faces of the prochiral oxocarbenium ion are subject to nucleophilic addition to
24 each case, reinforcing the involvement of an oxocarbenium ion as the common intermediate of this cruc
26 e, the deoxyribose ring exhibits significant oxocarbenium ion character with bond breaking (r(C-N) =
29 ions parallels the relative stability of the oxocarbenium ion conformers involved, as assessed by cal
33 In this reaction, TMSOTf is used to form the oxocarbenium ion in situ under conditions compatible wit
34 to occur within the active site to bring the oxocarbenium ion intermediate and Glu 89 closer by 4-5 A
36 e experimental findings, suggesting that the oxocarbenium ion intermediate is responsible for the deg
37 oceed via a nonstabilized, aliphatic, cyclic oxocarbenium ion intermediate paired with the confined c
38 ld provide electrostatic stabilization of an oxocarbenium ion intermediate that is formed by dissocia
39 1 by a hydrogen exposes an enzyme-stabilized oxocarbenium ion intermediate to reaction with external
40 ChEWL, which is postulated to stabilize the oxocarbenium ion intermediate, has no counterpart in GoE
43 ibuted to rates of nucleophilic additions to oxocarbenium ion intermediates that approach the diffusi
46 er, the region of IR that corresponds to the oxocarbenium ion is translocated in the direction of the
48 ransition state stabilization of the ribosyl oxocarbenium ion occur from neighboring group interactio
49 be disfavored by destabilizing the resultant oxocarbenium ion or by stabilizing an intermediate tetra
50 toms (O5 and C2 atoms), similar to either an oxocarbenium ion or N-acetylgalactal form, which are cry
52 ently linked anomeric phosphates rather than oxocarbenium ion pairs as the reactive intermediates.
55 lying that RpfB acts via the formation of an oxocarbenium ion rather than a covalent intermediate.
56 c systems, invoking an intermediate glycosyl oxocarbenium ion reacting through a boat conformation.
57 ypical Prins cyclization conditions when the oxocarbenium ion resulting from the rearrangement is sim
58 ocation and of formaldehyde to give a simple oxocarbenium ion results in very little change in the re
59 ite of HOBt followed by the extrusion of the oxocarbenium ion that was attacked by the glycosyl accep
60 tes by a cationic gold(I) catalyst yields an oxocarbenium ion that we previously showed is trapped by
61 reoselective capture of an in situ generated oxocarbenium ion via an intramolecular Friedel-Crafts al
63 esence of an axial alkoxy group distorts the oxocarbenium ion, changing its inherent preferences for
64 n largely considered as the chemistry of the oxocarbenium ion, e.g., direct rupture of the C1'-N1 bon
65 proach is anti to the C-2 substituent of the oxocarbenium ion, regardless of the ground-state conform
66 lization proceeding directly through a vinyl oxocarbenium ion, simulations identified an alternative
69 a direct displacement mechanism involving an oxocarbenium ion-like transition state assisted with Asp
70 ctivation mechanism with the formation of an oxocarbenium ion-like transition state, a hypothesis tha
83 ic anti aldol reaction and a two-directional oxocarbenium ion/vinyl silane condensation were employed
85 t the enzyme stabilizes a highly dissociated oxocarbenium ionlike transition state with very low bond
86 lyl cyanide with five- and six-membered ring oxocarbenium ions are attributed to the high reactivity
87 ehydes while reductions of the five-membered oxocarbenium ions are consistent with Woerpel's models.
89 pical carbon-based nucleophiles (sp(2) C) on oxocarbenium ions are very different, with the former be
90 ucleophilic substitution reactions of cyclic oxocarbenium ions at high reaction rates are discussed.
91 y in reductions of alpha-silyloxy 5-membered oxocarbenium ions based on stereoelectronic effects are
93 "inside attack" model for five-membered ring oxocarbenium ions developed previously for tetrahydrofur
94 lowest energy conformers of the intermediate oxocarbenium ions display the C-3 alkoxy group in a pseu
95 e Prins cyclization of the sulfur-stabilized oxocarbenium ions generated from acetals 14a-e or 15a-e
96 stituted alpha-methoxystyrenes (X-1) to form oxocarbenium ions have been computed using the second-or
97 Nucleophilic attack on seven-membered-ring oxocarbenium ions is generally highly stereoselective.
98 for 2,3-trans-substituted five-membered ring oxocarbenium ions is strongly influenced by the presence
99 at nucleophilic attack on five-membered ring oxocarbenium ions occurs from the inside face of the env
100 lic attack of putative intermediate glycosyl oxocarbenium ions suggests that the observed selectiviti
101 Vinyl ethers can be protonated to generate oxocarbenium ions that react with Me3SiCN to form cyanoh
102 ative cleavage reactions can be used to form oxocarbenium ions that react with pendent epoxides to fo
103 nzoquinone (DDQ) to form persistent aromatic oxocarbenium ions through oxidative carbon-hydrogen clea
106 stituted alpha-methoxystyrenes (X-1) to form oxocarbenium ions X-2(+) in 50/50 (v/v) HOH/DOD were cal
107 reactions of the acetals, which proceed via oxocarbenium ions, are operating under Felkin-Anh contro
108 proceeded via pseudoequatorially substituted oxocarbenium ions, as would be expected by consideration
109 kyl groups favor equatorial positions in the oxocarbenium ions, but alkoxy groups prefer axial confor
110 nformational preferences of the intermediate oxocarbenium ions, including the mannosyl cation, as wel
119 molecules are electronically similar to the oxocarbenium-like dissociative hPNP transition state, DA
120 ects are remarkable because they indicate an oxocarbenium-like ribose ring at the transition state bu
121 of a positive charge at mannosyl C1, as the oxocarbenium-like transition state is approached, is com
122 copyranosyl-2,5-imino-D-mannitol (DDGIM), an oxocarbenium mimic, was solved to 2.5 A resolution.
124 hod is expanded by the generation of alkenyl-oxocarbenium species as highly activated alkene intermed
125 osylases have been proposed to go through an oxocarbenium species that would trap the 6-hydroxyl moie
126 ate, products and a mimetic of the transient oxocarbenium species, which were prepared by synthesis.
128 ferential attack on the opposite face of the oxocarbenium to the C2-H2 bond and that eclipsing intera
129 GDP-2F-alpha-d-mannose, for which a cationic oxocarbenium transition state would be destabilized by e
131 ate is consistent with the involvement of an oxocarbenium transition-state structure, which has been
WebLSDに未収録の専門用語（用法）は "新規対訳" から投稿できます。