ChemInform Abstract: ORGANOIRON COMPLEXES IN ORGANIC SYNTHESIS. PART 2. CONFORMATIONAL AND STERIC EFFECTS OF METHYL SUBSTITUENTS IN TRICARBONYLIRON DERIVATIVES OF BICYCLO(4.4.0)DECADIENES

1978 ◽  
Vol 9 (49) ◽  
Author(s):  
A. J. PEARSON
Keyword(s):  
Organic Synthesis ◽  
Steric Effects ◽  
Organoiron Complexes ◽  
Derivatives Of

scholarly journals N-Directed Pd-Catalyzed Photoredox-Mediated C–H Arylation for Accessing Phenyl-Extended Analogues of Biginelli/Suzuki-Derived Ethyl 4-Methyl-2,6-diphenylpyrimidine-5-carboxylates

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1071
Author(s):  
Savvas N. Georgiades ◽  
Persefoni G. Nicolaou ◽  
Nikos Panagiotou
Keyword(s):  
Organic Synthesis ◽  
Phenyl Ring ◽  
Room Temperature ◽  
Functional Group ◽  
Cross Coupling ◽  
Steric Effects ◽  
Biologically Relevant ◽  
Biginelli Condensation ◽  
Derivatives Of ◽  
Electronic And Steric Effects

The availability and application of direct, functional group-compatible C–H activation methods for late-stage modification of small-molecule bioactives and other valuable materials remains an ongoing challenge in organic synthesis. In the current study, we demonstrate that a LED-activated, photoredox-mediated, Pd(OAc)2-catalyzed C–H arylation, employing a phenyldiazonium aryl source and either tris(2,2′-bipyridine)ruthenium(II) or (2,2′-bipyridine)bis[3,5-di-fluoro-2-[5-(trifluoromethyl)-2-pyridinyl-kN][phenyl-kC]iridium(III) as photoredox initiator, may successfully produce unprecedented mono- and bis-phenyl derivatives of functionality-rich 2,6-diphenylpyrimidine substrates at room temperature. The series of 19 substrates employed herein, which share the biologically-relevant 4-methyl-2,6-diphenylpyrimidine-5-carboxylate scaffold, were generated via a synthetic route involving (3-component) Biginelli condensation, oxidative dehydrogenation of the obtained 3,4-dihydropyrimidin-2(1H)-one to 2-hydroxypyrimidine, O-sulfonylation, and Suzuki-Miyaura C–C cross-coupling. Submission of these substrates to pyrimidine-N-atom-directed C–H arylation conditions led to regioselective phenylation at the ortho site(s) of the pyrimidine-C2-connected phenyl ring, revealing substituent-dependent electronic and steric effects. A focused library of 18 mono- and 10 bis-phenyl derivatives was generated. Its members exhibit interesting 3D and peripheral substitution features that render them promising for evaluation in drug discovery efforts.

Conformational analysis and steric effects of substituents in derivatives of 3-oxo-, 3-imino-, and 3-methylenecyclohexene

1997 ◽  
Vol 46 (11) ◽  
pp. 1891-1896
Author(s):  
O. V. Shishkin ◽  
E. V. Solomovich ◽  
M. Yu. Antipin ◽  
A. S. Petrenko ◽  
L. A. Kutulya
Keyword(s):  
Conformational Analysis ◽  
Steric Effects ◽  
Derivatives Of

Nuclear magnetic resonance characterization of the ring conformations of monosubstituted derivatives of 1,3-dioxa-5,6-benzocycloheptene

1983 ◽  
Vol 61 (1) ◽  
pp. 109-115 ◽  
Author(s):  
R. St-Amour ◽  
M. St-Jacques
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Substituent Effects ◽  
Steric Effects ◽  
Slow Exchange ◽  
Conformational Properties ◽  
Derivatives Of ◽  
Ring Conformations ◽  
Twist Boat

The conformational properties of 2-alkyl (Me, Et, i-Pr, and t-Bu) and 2-phenyl derivatives of 1,3-dioxa-5,6-benzocycloheptene (1) were studied by 13C dnmr. Analysis of slow exchange spectra at 100.6 MHz indicates that all derivatives except tert-butyl exist in an equilibrium of chair (major) and twist-boat (minor) conformations. Substituent effects on the position of the equilibrium are rationalized in terms of steric effects.

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