I2-Mediated Diversity Oriented Diastereoselective Synthesis of Amino Acid Derived trans-2,5-Disubstituted Morpholines, Piperazines, and Thiomorpholines
摘要:
Diastereoselective trans-2,5-disubstituted amino acids derived diverse morpholines, piperazines and thiomorpholines were prepared in 30 min-1 h with high yields through iodine-mediated 6-exotrig type cyclization from a single common synthetic intermediate. The displacement of iodine with hydride ion gave a methyl substituent at the 2-position of morpholines which provides an additional opportunity for diversity oriented nucleophilic substitution on the rings as well as incorporation of substituents at the 5-position from amino acids constituents.
Azabicyclo[3.1.0]hexane-1-ols as frameworks for the asymmetric synthesis of biologically active compounds
作者:Mouhamad Jida、Régis Guillot、Jean Ollivier
DOI:10.1016/j.tetlet.2007.10.003
日期:2007.12
obtained by Ti(IV)-mediated cyclopropanation of amino acid derivatives, constitute versatile, and unprecedented intermediates for the asymmetric synthesis of pharmacologically active products. Indeed, through selective rearrangement, these compounds undergo unusual ring cleavage to lead to pyrrolidinones. Fe(III)-promoted ring opening followed by basic dehydrohalogenation furnishes opticallyactive dihydropyridinones
LiOH-mediated N-monoalkylation of α-amino acid esters and a dipeptide ester using activated alkyl bromides
作者:Jong Hyun Cho、B.Moon Kim
DOI:10.1016/s0040-4039(01)02394-2
日期:2002.2
Selective N-monoalkylation of α-aminoesters with activated alkyl bromides was studied using various alkali or alkali earth metal bases. In the production of N-monoalkylated amino ester derivatives and suppression of N,N-dialkylation, lithium hydroxide was more effective than any other alkali or alkali earth bases examined. Using this protocol, a variety of N-alkylated α-aminoesters and even dipeptide