1093646-66-2Relevant academic research and scientific papers
Direct amino acid-catalyzed cascade biomimetic reductive alkylations: Application to the asymmetric synthesis of Hajos-Parrish ketone analogues
Ramachary, Dhevalapally B.,Kishor, Mamillapalli
supporting information; experimental part, p. 4176 - 4187 (2009/02/07)
A direct amino acid-catalyzed chemo- and enantioselective process for the double cascade synthesis of highly substituted 2-alkyl-cyclopentane-1,3-diones, 2-alkyl-3-methoxy-cyclopent-2-enones and Hajos-Parrish (H-P) ketone analogs is presented via reductive alkylation chemistry. For the first time, we have developed a single-step alkylation of cyclopentane-1,3-dione with aldehydes/ketones and a Hantzsch ester through an organocatalytic reductive alkylation strategy. A direct combination of amino acid-catalyzed cascade olefination-hydrogenation and cascade Robinson annulations of cyclopentane-1,3-dione, aldehydes/ketones, a Hantzsch ester and methyl vinyl ketone furnished the highly functionalized H-P ketone analogues in good to high yields and with excellent enantioselectivities. Many of the reductive alkylation products have shown direct applications in pharmaceutical chemistry.
High yielding selective access to spirocyclopropanated 5-oxopiperazine-2- carboxylates and 1,4-diazepane-2,5-diones from methyl 2-chloro-2- cyclopropylideneacetate
Limbach, Michael,Korotkov, Vadim S.,Es-Sayed, Mazen,De Meijere, Armin
experimental part, p. 3816 - 3822 (2009/02/05)
The 2-spirocyclopropanated methyl 5-oxopiperazine-2-carboxylate 3 and the 3-spirocyclopropanated 6-chloro-1,4-diazepane-2,5-dione 4 could both be prepared at choice in 93 and 88% yield, respectively, from methyl 2-chloro-2- cyclopropylideneacetate (1) in a sequence of Michael addition of 3-benzyloxypropylamine, peptide coupling with N-Boc-glycine, Boc-group removal and cyclization. Transformation of the benzyloxypropyl side chain, peptide coupling with N-Boc-(S)-asparagine, deprotection and repeated cyclization led to the octahydro[2H]pyrazino[1,2-a]pyrazinetrione scaffold 10 containing a rigidified mimic of a tripeptide with a DGR motif. The overall yield of 11 after deprotection of 10 (a total of 13 steps in 8 distinct operations) was 30%. The Royal Society of Chemistry 2008.
Synthesis of 7a-substituted Hajos-Wiechert ketone analogues
Kennedy, Jason W. J.,Vietrich, Sophia,Weinmann, Hilmar,Brittain, Dominic E. A.
, p. 5151 - 5154 (2008/09/21)
(Chemical Equation Presented) A general and efficient route to 2-substituted 1,3-cyclopentadiones 3 has been developed. This operationally simple, two-step procedure is amenable to multigram scale preparations of these useful synthetic intermediates. These compounds are then transformed to previously unknown, higher analogues of the Hajos-Parrish-Eder-Sauer-Wiechert ketone (enone 1, R = Me) following an enantioselective Robinson annulation.
