Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives
摘要:
Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective gamma-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective gamma-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronudeophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective gamma-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched alpha,alpha-disubstituted alpha-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and gamma-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nudeophilic oxazolide and the electrophilic phosphonium intermediate.
申请人:Board of Trustees of MICHIGAN STATE UNIVERSITY
公开号:US20030232998A1
公开(公告)日:2003-12-18
A new class of imidazolines as 4-position acids or esters with very potent anti-inflammatory as well as antimicrobial activity is described. The synthesis of these imidazolines includes a multicomponent reaction applicable to a combinatorial synthetic approach. The combination of these two key characteristics provides an effective therapeutic drug in the treatment of septic shock as well as many other inflammatory (arthritis and asthma) and infectious disorders. The use of this novel class of non-steroidal agents as anti-inflammatory agents (for the treatment of asthma, etc.), antibacterial agents, and antiseptic agents is described. The compounds are also useful in the treatment of tumors (such as cancers). The imidazolines are potent inhibitors of the transcription factor NF-&kgr;B as well as potent activity against the Gram (+) bacterium. The compositions are also useful for treating autoimmune diseases and for inhibiting rejection of organ and tissue transplants.
Multicomponent Synthesisof Highly Substituted Imidazolines via a Silicon Mediated 1,3-DipolarCycloaddition
作者:J. J. Tepe、S. Peddibhotla
DOI:10.1055/s-2003-40196
日期:——
multicomponent synthesis of highly functionalized imidazolines is reported. A silicon mediated 1,3 dipolar cycloaddition of the in situ generated munchnone with an imine resulted in the formation ofhighly substituted imidazolines. The imidazolines contain a four-point diversity and two stereocenters and the cycloaddition reaction is applicable to aryl, alkyl, acyl, and heterocyclic substitutions.
A new class of imidazolines as 4-position esters with very potent anti-inflammatory as well as antimicrobial activity is described. The synthesis of these imidazolines includes a multicomponent reaction applicable to a combinatorial synthetic approach. The combination of these two key characteristics provides an effective therapeutic drug in the treatment of septic shock as well as many other inflammatory (arthritis and asthma) and infectious disorders. The use of this novel class of non-steroidal agents as anti-inflammatory agents (for the treatment of asthma, etc.), antibacterial agents, and antiseptic agents is described. The compounds are also useful in the treatment of tumors (such as cancers). The imidazolines are potent inhibitors of the transcription factor NF-kB as well as potent activity against the Gram (+) bacterium. The compositions are also useful for treating autoimmune diseases and for inhibiting rejection of organ and tissue transplants.
Regioselective Synthesis of Tetrasubstituted Pyrroles by 1,3-Dipolar Cycloaddition and Spontaneous Decarboxylation
作者:Yongju Kim、Jonghoon Kim、Seung Bum Park
DOI:10.1021/ol8022193
日期:2009.1.1
We developed a novel regioselective synthesis of tetrasubstituted pyrroles via the classic 1,3-dipolar cycloaddition of alpha,beta-unsaturated benzofuran-3(2h)-one and azlactones (1) followed by spontaneous decarboxylation. The complete regiochemical control of tetrasubstituted pyrroles was confirmed by the orthogonal synthesis of complementary regioisomers (7a and 7b) simply by using different azlactones (1a and 1b, respectively).