73406-74-3Relevant academic research and scientific papers
Base-promoted aromatic [3,3] sigmatropic rearrangement of N-acyl-O-arylhydroxylamine derivatives
Tayama, Eiji,Hirano, Kazuki
, p. 665 - 673 (2019/01/04)
The base-promoted aromatic [3,3] sigmatropic rearrangement of N-acyl-O-arylhydroxylamines giving α-(2-hydroxyphenyl)amides was successfully demonstrated. The substrates were prepared from N-substituted hydroxylamines by N-acylation followed by copper(I)-mediated O-arylation with boronic acids. Treatment of the substrates with lithium hexamethyldisilazide (LiHMDS) in THF at 0 °C to room temperature generated the corresponding amide enolates. The aromatic [3,3] rearrangement of the enolates provided the desired products in moderate to good yields. A crossover experiment produced only intramolecular products and clarified that the reaction proceeds via the aromatic [3,3] sigmatropic rearrangement, not a bond-cleavage–recombination process. Our method is a formal α-arylation of amides.
Direct enantioselective: C -acylation for the construction of a quaternary stereocenter catalyzed by a chiral bicyclic imidazole
Wang, Mo,Zhang, Xiao,Ling, Zheng,Zhang, Zhenfeng,Zhang, Wanbin
supporting information, p. 1381 - 1384 (2017/02/05)
A direct enantioselective C-acylation of 3-substituted benzofuran-2(3H)-ones (with up to 97% ee) was developed using a chiral bicyclic imidazole catalyst OAc-DPI and an achiral tertiary amine additive DIPEA. The reaction mechanism for the direct C-acylation has been investigated using both experimental and theoretical studies.
A palladium-catalyzed regioselective hydroesterification of alkenylphenols to lactones with phenyl formate as CO source
Wang, Haining,Dong, Ben,Wang, Yang,Li, Jingfu,Shi, Yian
supporting information, p. 186 - 189 (2014/01/23)
An effective Pd(OAc)2-PPh3 catalyzed hydroesterification of alkenylphenols with phenyl formate as CO surrogate is described. A variety of lactones are obtained in generally high yields with high regioselectivities. In one case, 76% ee is obtained with a chiral ligand.
N-heterocyclic carbene catalysed oxygen-to-carbon carboxyl transfer of indolyl and benzofuranyl carbonates
Thomson, Jennifer E.,Kyle, Andrew F.,Gallagher, Katherine A.,Lenden, Philip,Concellon, Carmen,Morrill, Louis C.,Miller, Andrew J.,Joannesse, Caroline,Slawin, Alexandra M. Z.,Smith, Andrew D.
experimental part, p. 2805 - 2818 (2009/04/04)
The ability of N-heterocyclic carbenes to promote O-to-C carboxyl transfer on a range of indolyl and benzofuranyl carbonates is examined, and the scope and limitations of this process delineated. Georg Thieme Verlag Stuttgart.
Enantioselective TADMAP-catalyzed carboxyl migration reactions for the synthesis of stereogenic quaternary carbon
Shaw, Scott A.,Aleman, Pedro,Christy, Justin,Kampf, Jeff W.,Va, Porino,Vedejs, Edwin
, p. 925 - 934 (2007/10/03)
The chiral, nucleophilic catalyst TADMAP [1, 3-(2,2,2-triphenyl-1- acetoxyethyl)-4-(dimethylamino)-pyridine] has been prepared from 3-lithio-4-(dimethylamino)pyridine (5) and triphenylacetaldehyde (3), followed by acylation and resolution. TADMAP catalyzes the carboxyl migration of oxazolyl, furanyl, and benzofuranyl enol carbonates with good to excellent levels of enantioselection. The oxazole reactions are especially efficient and are used to prepare chiral lactams (23) and lactones (30) containing a quaternary asymmetric carbon. TADMAP-catalyzed carboxyl migrations in the indole series are relatively slow and proceed with inconsistent enantioselectivity. Modeling studies (B3LYP/6-31G*) have been used in qualitative correlations of catalyst conformation, reactivity, and enantioselectivity.
Lactone-derived carbon-centered radicals: Formation and reactivity with oxygen
Bejan, Elena V.,Font-Sanchis, Enrique,Scaiano
, p. 4059 - 4062 (2007/10/03)
matrix presented Several lactones were examined to test the reactivity of carbon-centered radicals toward oxygen. Notably, the radical derived from 2-coumaranone (4) is unreactive toward oxygen, while 2-cuomaranone itself shows enhanced reactivity toward hydrogen abstraction by alkoxyl radicals. We propose that five parameters influence diminished reactivity toward oxygen, i.e., (a) benzylic resonance stabilization, (b) unpaired spin delocalization on oxygen, (c) favorable stereoelectronic effects, (d) electron-withdrawing effects, and (e) steric effects.
Rhodium-catalysed cyclic carbonylation of 2-alkynylphenols: Synthesis of benzofuranones and coumarins
Yoneda, Eiji,Sugioka, Takashi,Hirao, Kojiro,Zhahg, Shi-Wei,Takahashi, Shigetoshi
, p. 477 - 483 (2007/10/03)
Rhodium-catalysed carbonylation of 2-alkynylphenols 1 under water-gas shift reaction conditions gives benzofuranone derivatives 2 and coumarin derivatives 3 in high yield (up to 96%, 2:3 = 65:35), in which the hydroxy group adjacent to the carbon-carbon triple bond participitates in the cyclic carbonylation.
Synthesis and hydrolysis kinetics of 4-cyano-4-phenylpiperidine derivatives: A route to morphine analogs
Gervais,Anker,Chareire,Pacheco
, p. 241 - 248 (2007/10/05)
A description is given of a high-yield synthesis leading to various hydroxy-2 phenylacetonitriles and to various benzodihydro-2,3 furannones-2. The intermediary 12 benzylic mesylates give quantitatively the corresponding 11 chlorides by the action of hydrochlorate of triethylamine; this procedure constitutes a very rewarding and easy method for chlorinating the benzylic alcohols in two stages without isolating the intermediary. A proximate effect has been shown which makes possible the hydrolysis of certain phenylacetonitriles by dilute acetic acid. This hydrolysis becomes very rapid when these nitriles are distributed; the increase of the speed of the hydrolysis illustrates the gem dialkyle effect.
