Spiro[2.2]pentane as a Dissymmetric Scaffold for Conformationally Constrained Analogues of Glutamic Acid: Focus on Racemic 1-Aminospiro[2.2]pentyl-1,4-dicarboxylic Acids
摘要:
In search for novel conformationally constrained analogues of L-glutamic acid, a diastereodivergent synthesis of the four 1-aminospiro[2.2]pentyl-1,4-dicarboxylic acid racernic pairs is reported along with their stereochemical assignment, conformational analysis, and preliminary biological evaluation as potential glutamate (ionotropic and metabotropic) ligands.
Spiro[2.2]pentane as a Dissymmetric Scaffold for Conformationally Constrained Analogues of Glutamic Acid: Focus on Racemic 1-Aminospiro[2.2]pentyl-1,4-dicarboxylic Acids
摘要:
In search for novel conformationally constrained analogues of L-glutamic acid, a diastereodivergent synthesis of the four 1-aminospiro[2.2]pentyl-1,4-dicarboxylic acid racernic pairs is reported along with their stereochemical assignment, conformational analysis, and preliminary biological evaluation as potential glutamate (ionotropic and metabotropic) ligands.
Site- and Regioselective Silaborative C–C Cleavage of 1-Alkyl-2-Methylenecyclopropanes Using a Platinum Catalyst with a Sterically Demanding Silylboronic Ester
presence of a phosphine-free platinum catalyst, giving 3-substituted 2-boryl-4-silyl-1-butenes throughselectivecleavage of the less hindered proximalC–Cbond of the cyclopropane ring. The steric bulk of the silyl group of the silylboronic esters was critical for efficient formation of the silaboration products, and i-PrPh2Si–B(pin) was developed as a silylboronic ester of choice.
A nickel-catalyzed [4 + 1] cycloaddition of enones with methylenecyclopropanes leading to dihydrofurans was developed. The reaction outcome is attributed to the transformation of methlenecyclopropane, which is incorporated Into a five-membered ring as a one-carbon fragment.
Kinetic Resolution of Racemic 1-Alkyl-2-methylenecyclopropanes via Palladium-Catalyzed Silaborative C−C Cleavage
Kinetic resolution of racemic 1-alkyl-2-methylenecyclopropanes via silaborative C-C cleavage was efficiently catalyzed by a palladium complex bearing a chiral phosphoramidite, affording 2-boryl-3-silylmethyl-1-alkenes as major products with up to 92% ee. Enantioenrichment through parallel kinetic resolution, where the slower reacting enantiomer was converted to the constitutional isomer of the major product, may be involved as the crucial stereodiscriminating step.
Spiro[2.2]pentane as a Dissymmetric Scaffold for Conformationally Constrained Analogues of Glutamic Acid: Focus on Racemic 1-Aminospiro[2.2]pentyl-1,4-dicarboxylic Acids
作者:Roberto Pellicciari、Maura Marinozzi、Emidio Camaioni、Maria del Carmen Nùnez、Gabriele Costantino、Fabrizio Gasparini、Gianluca Giorgi、Antonio Macchiarulo、Natarajan Subramanian
DOI:10.1021/jo020138v
日期:2002.8.1
In search for novel conformationally constrained analogues of L-glutamic acid, a diastereodivergent synthesis of the four 1-aminospiro[2.2]pentyl-1,4-dicarboxylic acid racernic pairs is reported along with their stereochemical assignment, conformational analysis, and preliminary biological evaluation as potential glutamate (ionotropic and metabotropic) ligands.