- Pd-catalyzed stereoselective tandem ring-opening amination/cyclization of vinyl γ-lactones: Access to caprolactam diversity
-
A stereoselective amination/cyclization cascade process has been developed that allows for the preparation of a series of unsaturated and substituted caprolactam derivatives in good yields. This conceptually novel protocol takes advantage of the easy access and modular character of vinyl γ-lactones that can be prepared from simple precursors. Activation of the lactone substrate in the presence of a suitable Pd precursor and newly developed phosphoramidite ligand offers a stereocontrolled ring-opening/allylic amination manifold under ambient conditions. The intermediate (E)-configured ?-amino acid can be cyclized using a suitable dehydrating agent in an efficient one-pot, two-step sequence. This overall highly chemo-, stereo- and regio-selective transformation streamlines the production of a wide variety of modifiable and valuable caprolactam building blocks in an operationally attractive way. This journal is
- Kleij, Arjan W.,Li, Xuetong,Xie, Jianing
-
-
Read Online
- Process for preparing 4-phenyl cycloheptylamine
-
The invention discloses a process for preparing 4-phenyl cycloheptylamine. The process comprises the following steps: 1) in the presence of a strong base, condensing 4-phenyl cyclohexanone and hydroxylammonium chloride in an appropriate solvent at an appr
- -
-
Paragraph 0020; 0028-0033
(2018/12/13)
-
- Direct Catalytic Desaturation of Lactams Enabled by Soft Enolization
-
A direct catalytic method is described for the α,β-desaturation of N-protected lactams to their conjugated unsaturated counterparts under mildly acidic conditions. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups, showing reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility of this method is demonstrated in a concise synthesis of Rolipram. In addition, linear amides also prove to be competent substrates, and the phthaloyl-protected product serves as a convenient precursor to access various conjugated carboxylic acid derivatives. Strong bases are avoided in this desaturation approach, and the key is to merge soft enolization with a Pd-catalyzed oxidation process.
- Chen, Ming,Dong, Guangbin
-
supporting information
p. 7757 - 7760
(2017/06/21)
-
- Remodeling and Enhancing Schmidt Reaction Pathways in Hexafluoroisopropanol
-
The effect of carrying out two variations of the Schmidt reaction with ketone electrophiles in hexafluoroisopropanol (HFIP) solvent has been studied. When TMSN3 is reacted with ketones in the presence of triflic acid (TfOH) promoter, tetrazoles are obtained as the major products. This observation is in contrast to established methods, which usually lead to amides or lactams arising from formal NH insertion as the major products. The full product profiles of several examples of this reaction are also reported and found to include mechanistically interesting products (e.g., double ring expansion). Application of TfOH promoter in HFIP was also found to promote the reaction of a hydroxyalkyl azide with a ketone, which affords lactams following nucleophilic opening of initially formed iminium ether more efficiently than previously reported methods. (Chemical Equation Presented).
- Motiwala, Hashim F.,Charaschanya, Manwika,Day, Victor W.,Aubé, Jeffrey
-
p. 1593 - 1609
(2016/03/01)
-
- Synthesis of chiral lactams: Via asymmetric hydrogenation of α,β-unsaturated nitriles
-
A highly efficient Rh-catalyzed enantioselective hydrogenation of α,β-unsaturated nitriles containing ester/amide groups has been developed. Under mild conditions, with a complex of rhodium and (S,S)-f-spiroPhos as the catalyst, a variety of α,β-unsaturated nitriles bearing an ester or amide group were successfully hydrogenated to the corresponding chiral nitriles with excellent enantioselectivities (up to 99.7% ee) and high turnover numbers (TON = 10000). Furthermore, this catalyst system was also successfully applied to the synthesis of important chiral pharmacophore fragments, lactams, Paroxetine and amino acids.
- Kong, Duanyang,Li, Meina,Zi, Guofu,Hou, Guohua
-
p. 4046 - 4053
(2016/06/14)
-
- Directing Group in Decarboxylative Cross-Coupling: Copper-Catalyzed Site-Selective C-N Bond Formation from Nonactivated Aliphatic Carboxylic Acids
-
Copper-catalyzed directed decarboxylative amination of nonactivated aliphatic carboxylic acids is described. This intramolecular C-N bond formation reaction provides efficient access to the synthesis of pyrrolidine and piperidine derivatives as well as the modification of complex natural products. Moreover, this reaction presents excellent site-selectivity in the C-N bond formation step through the use of directing group. Our work can be considered as a big step toward controllable radical decarboxylative carbon-heteroatom cross-coupling.
- Liu, Zhao-Jing,Lu, Xi,Wang, Guan,Li, Lei,Jiang, Wei-Tao,Wang, Yu-Dong,Xiao, Bin,Fu, Yao
-
supporting information
p. 9714 - 9719
(2016/08/11)
-
- Amidino derivatives useful as nitric oxide synthase inhibitors
-
The current invention discloses useful pharmaceutical compositions containing amidino derivative useful as nitric oxide synthase inhibitors.
- -
-
-
- Amidino dervatives useful as nitric oxide synthase inhibitors
-
The current invention discloses useful pharmaceutical compositions containing azepine derivatives useful as nitric oxide synthase inhibitors.
- -
-
-
- Beckmann Rearrangement of Oximes Catalyzed with Tetrabutylammonium Perrhenate and Trifluoromethanesulfonic Acid
-
The Beckmann rearrangement of oximes is catalyzed by a combined use of tetrabutylammonium perrhenate (Bu4NReO4) and trifluoromethanesulfonic acid in nitromethane under azeotropic conditions, giving amides in high yield.By employing this catalytic system, amides can be prepared directly from ketones and hydroxylamine hydrochloride.
- Kusama, Hiroyuki,Yamashita, Yuko,Narasaka, Koichi
-
p. 373 - 377
(2007/10/02)
-
- Beckmann Rearrangement Catalyzed by the Combined Use of Tetrabutylammonium Perrhenate(VII) and Trifluoromethanesulfonic Acid
-
Beckmann rearrangement of oximes is catalyzed with tetrabutylammonium perrhenate(VII), trifluoromethanesulfonic acid and hydroxylamine hydrochloride in nitromethane under azeotropic conditions, giving amides in high yield.
- Narasaka, Koichi,Kusama, Hiroyuki,Yamashita, Yuko,Sato, Hiroshi
-
p. 489 - 492
(2007/10/02)
-
