28077-64-7Relevant articles and documents
Manganese-catalyzed synthesis of cis-β-amino acid esters through organometallic C-H activation of ketimines
Liu, Weiping,Zell, Daniel,John, Michael,Ackermann, Lutz
, p. 4092 - 4096 (2015)
Manganese-catalyzed C-H functionalization reactions of ketimines set the stage for the expedient synthesis of cis-β-amino acid esters through site- and regioselective alkene annulations. The organometallic C-H activation occurred efficiently with high fun
CONFORMATIONAL ORDER IN CRYSTALLINE STATES AND GELS OF ISOTACTIC, SYNDIOTACTIC AND ATACTIC POLYSTYRENES STUDIED BY VIBRATIONAL SPECTROSCOPY
Nakaoki, Takahiko,Kobayashi, Masamichi
, p. 315 - 331 (1991)
Stable conformations and their sequential order of isotactic (IPS), syndiotactic (SPS) and atactic polystyrenes (APS) in various aggregation states have been investigated by infrared (IR) spectroscopy, 13C NMR and X-ray diffraction.It has been demonstrated that the partially ordered skeletal conformation existing in IPS/CS2 gels of a (3/1) helix (TG) type having the pendant phenyl groups oriented in a disordered fashion, rather than the near-TT form proposed previously for IPS/decalin gels.The process of conformational change during gelation of IPS/CS2 and APS/CS2 systems has been followed by IR spectroscopy, and it has been concluded that the construction of regular sequences of a particular conformation promotes the gelation of both crystallizable and non-crystallizable polystyrenes.As-cast film specimens prepared from a chloroform solution are found to be a crystalline polymer-solvent complex (the γ phase) having a TTGG conformation.On heating, the γ phase transforms to a β phase at about 120 deg C, accompanied by removal of the solvent, while the TTGG conformation is retained.On further heating, the β phase transforms to an α1 or α2 phase at about 200 deg C accompanied by a change in conformation from TTGG to TT.The process of conformational change (in both type and sequence) during these phase transformations has been clarified by IR spectroscopy.
Rhodium-Catalyzed Annulation of Phenacyl Ammonium Salts with Propargylic Alcohols via a Sequential Dual C-H and a C-C Bond Activation: Modular Entry to Diverse Isochromenones
Nanubolu, Jagadeesh Babu,Reddy Singam, Maneesh Kumar,Sridhar Reddy, Maddi,Suresh, Vavilapalli,Suri Babu, Undamatla
supporting information, p. 7888 - 7893 (2021/10/25)
Given their omnipresence in natural products and pharmaceuticals, isochromenone congeners are one of the most privileged scaffolds to synthetic chemists. Disclosed herein is a dual (ortho/meta) C-H and C-C activation of phenacyl ammonium salts (acylammonium as traceless directing group) toward annulation with propargylic alcohols to accomplish rapid access for novel isochromenones by means of rhodium catalysis from readily available starting materials. This operationally simple protocol features broad substrate scope and wide functional group tolerance. Importantly, the protocol circumvents the need of any stoichiometric metal oxidants and proceeds under aerobic conditions.
Rhodium-Catalyzed Spiro Indenyl Benzoxazine Synthesis via C-H Activation/Annulation of 3-Aryl-2H-Benzo[b][1,4]oxazines and Alkynes
Tan, Heng,Laishram, Ronibala Devi,Zhang, Xuexin,Shi, Guangrui,Li, Kangkui,Chen, Jingchao
supporting information, p. 4542 - 4546 (2020/07/04)
The rhodium (III)-catalyzed annulation of 3-Aryl-2H-Benzo[b][1,4]oxazines with alkynes via C–H activation has been developed. This reaction afforded a series of spiro indenyl benzoxazine in high yields under mild reaction condition with good functional group tolerance.
