A New Candidate for a Properly Substituted CD Ring Component of Vitamin D3 via Intramolecular Asymmetric Olefination of a 1,3-Cyclopentanedione Derivative
摘要:
A highly diastereoselective synthesis of hydrindenone derivative 5 (98% de) was achieved via diastereotopic differentiation of 1,3-cyclopentanedione derivative 4 by intramolecular Horner-Emmons olefination. In addition, the compound 5 was converted to ketone 2, a new building block far 1 alpha,25-dihydroxyvitamin D-3 (1).
A New Candidate for a Properly Substituted CD Ring Component of Vitamin D3 via Intramolecular Asymmetric Olefination of a 1,3-Cyclopentanedione Derivative
摘要:
A highly diastereoselective synthesis of hydrindenone derivative 5 (98% de) was achieved via diastereotopic differentiation of 1,3-cyclopentanedione derivative 4 by intramolecular Horner-Emmons olefination. In addition, the compound 5 was converted to ketone 2, a new building block far 1 alpha,25-dihydroxyvitamin D-3 (1).
Synthesis of Racemic and Enantiomerically Pure Acetylenic ω-Keto Esters Derived from 2-Methyl-1,3-cycloalkanediones and 2-Methylcycloalkanones Respectively
Racemic and enantiomericallypure alkynyl esters tethered, respectively, to 2-methyl-1,3-cycloalkanediones and 2-methylcycloalkanones were readily obtained starting from common intermediates, which were available on large scale. alkynyl ester - enantiomer-chain - elongation - trimethylsilylpropyne - Corey-Fuchs reaction
We describe a synthetic method for a bicyclo[2.2.1]heptane skeleton with two oxy-functionalized bridgehead carbons. This method involves an intermolecular Diels–Alder reaction using 5,5-disubstituted 1,4-bis(silyloxy)-1,3-cyclopentadienes, the diene structure of which has never been synthesized. Furthermore, the intramolecular Diels–Alder reaction using a diene bearing a dienophile moiety at the C-5