102222-77-5Relevant academic research and scientific papers
Iridium-Catalyzed Regioselective Hydroalkynylation of Internal Alkenes Directed by an Oxime
Gao, Peng-Chao,Li, Bi-Jie,Wang, Zi-Xuan
supporting information, p. 9500 - 9504 (2021/12/14)
We report here an iridium-catalyzed hydroalkynylation of allylic alcohols protected by an oxime group. Catalytic alkynylation occurs exclusively at the distal position of the alkene. This method generates γ-alkynyl alcohol oximes directly from internal alkenes and terminal alkynes. The oxime group can be readily removed to afford a free alcohol, thus providing an indirect route for the catalytic hydroalkynylation of allylic alcohols.
C-H bond functionalization via hydride transfer: Formation of α-arylated piperidines and 1,2,3,4-tetrahydroisoquinolines via stereoselective intramolecular amination of benzylic C-H bonds
Vadola, Paul A.,Carrera, Ignacio,Sames, Dalibor
experimental part, p. 6689 - 6702 (2012/10/18)
We here report a study of the intramolecular amination of sp3 C-H bonds via the hydride transfer cyclization of N-tosylimines (HT-amination). In this transformation, 5-aryl aldehydes are subjected to N-toluenesulfonamide in the presence of BF3?OEt2 to effect imine formation and HT-cyclization, leading to 2-arylpiperidines and 3-aryl-1,2,3,4- tetrahydroisoquinolines in a one-pot procedure. We examined the reactivity of a range of aldehyde substrates as a function of their conformational flexibility. Substrates of higher conformational rigidity were more reactive, giving higher yields of the desired products. However, a single substituent on the alkyl chain linking the N-tosylimine and the benzylic sp3 C-H bonds was sufficient for HT-cyclization to occur. In addition, an examination of various arenes revealed that the electronic character of the hydridic C-H bonds dramatically affects the efficiency of the reaction. We also found that this transformation is highly stereoselective; 2-substituted aldehydes yield cis-2,5-disubstituted piperidines, while 3-substituted aldehydes afford trans-2,4-disubstituted piperidines. The stereoselectivity is a consequence of thermodynamic control. The pseudoallylic strain between the arene and tosyl group on the piperidine ring is proposed to rationalize the greater stability of the isomer with the aryl ring in the axial position. This preferential placement of the arene is proposed to affect the observed stereoselectivity.
Specific Inhibitors in Vitamin Biosynthesis. Part 8. Syntheses of some Functionalised 7,7-Dialkyl-7,8-dihydropterins
Cameron, Robert,Nicholson, Sydney H.,Robinson, David H.,Suckling, Colin J.,Wood, Hamish C. S.
, p. 2133 - 2144 (2007/10/02)
The synthesis of variety of functionalised blocked 7,8-dihydropteridines is described.The functional groups were chosen to provide compounds with potential for investigating the protein chemistry of enzymes in the pathway leading to dihydrofolate and, in particular, of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase.The potential of 7-substituents to provide sites of attachment of inhibitors to columns for affinity chromatography was explored but the extent of the study was curtailed by the restricted applicability of nitrosyl chloride addition to alkenes, a reaction used in the synthesis of pteridine precursors.The syntheses of two compounds, a 6-trichlorophenoxymethyldihydropteridine and of a thiadiazolopteridine, designed to have enchanced transport properties, are also described.
