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Sunderhaus JD, Dockendorff C, Martin SF. Applications of Multicomponent Reactions for the Synthesis of Diverse Heterocyclic Scaffolds. Org Lett 2007; 9:4223-6. [PMID: 17887692 DOI: 10.1021/ol7018357] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A four-component coupling process involving sequential reactions of aldehydes, primary amines, acid chlorides, and nucleophiles has been developed to prepare multifunctional substrates that may be employed in subsequent ring-forming reactions to generate a diverse array of functionalized heterocyclic scaffolds. This new approach to diversity-oriented synthesis was then applied to the first total synthesis of the isopavine alkaloid (+/-)-roelactamine.
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127
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Martin SF. The 2006 Tetrahedron Prize for Creativity in Organic Chemistry. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.06.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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128
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Sparks SM, Chen CL, Martin SF. Tandem Intramolecular Benzyne-Furan Cycloadditions. Total Synthesis of Vineomycinone B(2) Methyl Ester. Tetrahedron 2007; 63:8619-8635. [PMID: 18728697 DOI: 10.1016/j.tet.2007.04.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have exploited tandem intramolecular benzyne-furan cycloadditions employing three different benzyne precursors to generate substituted bisoxabenzonorbornadienes in a single operation. The regiochemical outcomes in these Diels-Alder reactions were effectively controlled by using disposable silicon tethers to link the reacting benzynes and furan moieties. Two different methods for converting the intermediate bisoxabenzonorbornadienes to substituted anthrarufins were developed. The first tactic entails the initial cleavage of the silicon tethers followed by regioselective ring opening of the oxabicycloheptadienes and oxidation of the central ring giving the target anthrarufin, whereas the second features the regioselective ring opening of the oxabicycloheptadienes followed by protiodesilylation and oxidation. When the starting furans bear carbohydrate substitutents, this new methodology enables the rapid assembly of the glycosyl-substituted aromatic cores of complex C-aryl glycoside antibiotics from simple starting materials. The utility of this novel approach to anthrarufins and C-aryl glycosides is exemplified in a triply convergent synthesis of vineomycinone B(2) methyl ester.
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129
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Martin SF. Celebrating the 50th Anniversary of Tetrahedron 1957–2007. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.04.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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130
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Martin SF. Celebrating the 50th Anniversary of Tetrahedron 1957–2007. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.04.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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131
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Simila STM, Martin SF. Toward the total synthesis of FR901483: concise synthesis of the azatricyclic skeleton. J Org Chem 2007; 72:5342-9. [PMID: 17555359 PMCID: PMC2536713 DOI: 10.1021/jo070732a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A concise synthesis of the azatricyclic core of FR901483 has been accomplished using a novel strategy that involves a nucleophilic addition to an N-acyl iminium ion, a ring-closing metathesis, a diastereoselective hydroboration, and a lactone-lactam rearrangement that worked well in a preliminary model study. Extension of this approach to the synthesis of a more highly functionalized intermediate that could be transformed into (-)-FR901483 first required the development of a new protecting group, the 1-ethylallyloxycarbamate group, for amines that may be removed under mild conditions. However, because the stereoselectivity in a key step in which a functionalized allyl zinc reagent was added to an intermediate hydroxy-substituted imine was low, this route to (-)-FR901483 is no longer being pursued.
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132
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Benfield AP, Whiddon BB, Clements JH, Martin SF. Structural and energetic aspects of Grb2-SH2 domain-swapping. Arch Biochem Biophys 2007; 462:47-53. [PMID: 17466257 PMCID: PMC1947945 DOI: 10.1016/j.abb.2007.03.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 03/09/2007] [Accepted: 03/10/2007] [Indexed: 12/31/2022]
Abstract
The SH2 domain of growth factor receptor-bound protein 2 (Grb2) has been the focus of numerous studies, primarily because of the important roles it plays in signal transduction. More recently, it has emerged as a useful protein to study the consequences of ligand preorganization upon energetics and structure in protein-ligand interactions. The Grb2-SH2 domain is known to form a domain-swapped dimer, and as part of our investigations toward correlating structure and energetics in biological systems, we examined the effects that domain-swapping dimerization of the Grb2-SH2 domain had upon ligand binding affinities. Isothermal titration calorimetry was performed using Grb2-SH2 in both its monomeric and domain-swapped dimeric forms and a phosphorylated tripeptide AcNH-pTyr-Val-Asn-NH(2) that is similar to the Shc sequence recognized by Grb2-SH2 in vivo. The two binding sites of domain-swapped dimer exhibited a 4- and a 13-fold reduction in ligand affinity compared to monomer. Crystal structures of peptide-bound and uncomplexed forms of Grb2-SH2 domain-swapped dimer were obtained and reveal that the orientation of residues V122, V123, and R142 may influence the conformation of W121, an amino acid that is believed to play an important role in Grb2-SH2 ligand sequence specificity. These findings suggest that domain-swapping of Grb2-SH2 not only results in a lower affinity for a Shc-derived ligand, but it may also affect ligand specificity.
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133
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Breton P, Hergenrother PJ, Hida T, Hodgson A, Judd AS, Kraynack E, Kym PR, Lee WC, Loft MS, Yamashita M, Martin SF. Total synthesis of erythromycin B. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.02.044] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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134
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Davoren JE, Martin SF. Enantioselective synthesis and structure revision of solandelactone E. J Am Chem Soc 2007; 129:510-1. [PMID: 17227012 PMCID: PMC2527536 DOI: 10.1021/ja068270q] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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135
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Abstract
A novel enantioselective total synthesis of (-)-alstonerine has been completed that requires only 15 steps from L-tryptophan. The synthesis features the first application of a Pauson-Khand reaction to synthesize an azabridged bicyclic skeleton. [reaction: see text]
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136
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Benfield AP, Goodey NM, Phillips LT, Martin SF. Structural studies examining the substrate specificity profiles of PC-PLC(Bc) protein variants. Arch Biochem Biophys 2007; 460:41-7. [PMID: 17324372 PMCID: PMC1905842 DOI: 10.1016/j.abb.2007.01.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 01/18/2007] [Accepted: 01/23/2007] [Indexed: 10/23/2022]
Abstract
The phosphatidylcholine preferring phospholipase C from Bacillus cereus (PC-PLC(Bc)) catalyzes the hydrolysis of phospholipids in the following order of preference: phosphatidylcholine (PC)>phosphatidylethanolamine (PE)>phosphatidylserine (PS). In previous work, mutagenic, kinetic, and crystallographic experiments suggested that varying the amino acids at the 4th, 56th, and 66th positions had a significant influence upon the substrate specificity profile of PC-PLC(Bc). Here, we report the crystal structures of the native form of several PC-PLC(Bc) variants that exhibited altered substrate specificities for PC, PE, and PS at maximum resolutions of 1.90-2.05 Angstrom. Comparing the structures of these variants to the structure of the wild-type enzyme reveals only minor differences with respect to the number and location of active site water molecules and the side chain conformations of residues at the 4th and 56th positions. These results suggest that subtle changes in steric and electronic properties in the substrate binding site of PC-PLC(Bc) are responsible for the significant changes in substrate selectivity.
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Benfield AP, Teresk MG, Plake HR, DeLorbe JE, Millspaugh LE, Martin SF. Ligand preorganization may be accompanied by entropic penalties in protein-ligand interactions. Angew Chem Int Ed Engl 2007; 45:6830-5. [PMID: 17001728 DOI: 10.1002/anie.200600844] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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138
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Kummer DA, Brenneman JB, Martin SF. Domino intramolecular enyne metathesis/cross metathesis approach to the xanthanolides. Enantioselective synthesis of (+)-8-epi-xanthatin. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.05.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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139
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140
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Benfield AP, Teresk MG, Plake HR, DeLorbe JE, Millspaugh LE, Martin SF. Ligand Preorganization May Be Accompanied by Entropic Penalties in Protein–Ligand Interactions. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600844] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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141
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Abstract
[reaction: see text] An enantioselective entry to the skeleton of the tremulane sesquiterpenes is described. The approach features a series of efficient transition metal-catalyzed reactions commencing with an enantioselective rhodium(II)-catalyzed intramolecular cyclopropanation followed by a regioselective allylic alkylation and a diastereoselective rhodium(I)-catalyzed [5 + 2] cycloaddition. This strategy was applied to the first enantioselective syntheses of tremulenediol A and tremulenolide A.
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142
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Sutko JL, Thompson LJ, Schlatterer RG, Lattanzio FA, Fairhurst AS, Campbell C, Martin SF, Deslongehamps P, Ruest L, Taylor DR. Separation and formation of ryanodine from dehydroryanodine. Preparation of tritium-labeled ryanodine. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580230212] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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143
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Deiters A, Pettersson M, Martin SF. General Strategy for the Syntheses of Corynanthe, Tacaman, and Oxindole Alkaloids. J Org Chem 2006; 71:6547-61. [PMID: 16901143 DOI: 10.1021/jo061032t] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report herein the total synthesis of the corynanthe alkaloid dihydrocorynantheol and the formal syntheses of the indole alkaloids tacamonine, rhynchophylline, and hirsutine. The strategies for assembling the corynanthe and tacaman skeletal frameworks comprised of both the classical ABD --> ABCD and ABC --> ABCD approaches wherein the variously substituted piperidinone D-rings were formed via ring-closing metathesis (RCM) followed by a 1,4-addition to introduce the requisite side chain at C(15). Since 1,4-additions to alpha,beta-unsaturated lactams represent an underdeveloped field, we conducted a series of studies with two unsaturated lactams employing organocuprates and metal enolates as the nucleophiles. These studies revealed that organocuprates derived from Grignard reagents and either stoichiometric amounts of CuCN or catalytic amounts of CuBr.DMS complex are excellent nucleophiles for such additions; TMSCl was a crucial additive for optimizing these reactions. The anion derived from ethyl 1,3-dithiolane-2-carboxylate was also an excellent nucleophile in these 1,4-additions, although the stereochemistry of such 1,4-additions to carboline-derived, unsaturated lactams was sensitive to substitution on the indole nitrogen atom. The ABD --> ABCD approach to these alkaloids featured a novel one-pot sequence of an RCM reaction and a zirconocene-catalyzed carbomagnesation followed by a second RCM to generate the D-ring.
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Abstract
Small peptides exhibit a wide range of biological activities, but although there are some notable exceptions, they are not generally useful as drugs. This has spurred widespread interest in designing peptidomimetics and introducing them as replacements of portions of native peptides to enhance their biological properties. Special attention has been focused upon rigid replacements because of their potential to preorganize the resulting pseudopeptide in a conformation corresponding to its bound structure. Toward this goal, we invented trisubstituted cyclopropanes as novel peptidomimetics, anticipating that the cyclopropane ring would locally orient the backbone and the corresponding amino acid side chain in the biologically active conformation. Selected aspects of the syntheses and applications of these cyclopropane-derived peptidomimetics are presented in this Account.
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145
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Chen CL, Martin SF. Pd-Catalyzed Ring Opening of Oxa- and Azabicyclic Alkenes with Aryl and Vinyl Halides: Efficient Entry to 2-Substituted 1,2-Dihydro-1-naphthols and 2-Substituted 1-Naphthols. J Org Chem 2006; 71:4810-7. [PMID: 16776506 DOI: 10.1021/jo060299p] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An efficient syntheses of 2-substituted 1,2-dihydro-1-naphthols and 2-substituted 1-naphthols has been developed that involves the sequential palladium-catalyzed ring opening of oxabicyclic alkenes with aryl and vinyl halides followed by oxidation of with IBX. In the first step of the sequence, a combination of Pd(OAc)2, PPh3, Zn, and PMP in dry DMF was employed to catalyze the ring opening of 7-oxabenzonorbornadienes with aryl and vinyl halides to afford the corresponding cis-2-substituted 1,2-dihydronaphthols in good to excellent yields. These reactions occurred under very mild conditions with a variety of aryl halides bearing electron-withdrawing or -donating groups. Similarly, a 7-azabenzonorbornadiene substituted with an electron-withdrawing group on the nitrogen atom underwent facile ring-opening reaction with aryl halides to provide cis-2-substituted (1,2-dihydro-1-naphthyl)carbamates in excellent yields. Oxidation of the intermediate 1,2-dihydro-1-naphthols using IBX yielded the corresponding 2-substituted 1-naphthols in good to excellent yields.
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146
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Li H, Procko K, Martin SF. Facile synthesis of C-aryl glycals from sugar-derived lactones. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.02.150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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147
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Simila ST, Reichelt A, Martin SF. Synthetic studies toward the immunosuppressant FR901483. Facile construction of the azatricyclic skeleton. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.02.116] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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148
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Abstract
[chemical reaction: see text]. Concise formal syntheses of marine alkaloids (+/-)-pinnaic acid (1) and (+/-)-halichlorine (2) have been accomplished from a common intermediate. The syntheses illustrate the utility of selective olefin cross metathesis methodologies for the elaboration of advanced synthetic intermediates in complex molecule synthesis.
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149
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Chen CL, Martin SF. Facile synthesis of 2-substituted 1,2-dihydro-1-naphthols and 2-substituted 1-naphthols. Org Lett 2005; 6:3581-4. [PMID: 15387553 DOI: 10.1021/ol048517t] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] The palladium-catalyzed ring opening of dimethoxy oxabenzonorbornadiene with aryl or vinyl halides occurred under very mild conditions to give substituted 1,2-dihydronaphthols that were oxidized with IBX to furnish substituted naphthols in excellent overall yields.
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150
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Kummer DA, Brenneman JB, Martin SF. Application of a Domino Intramolecular Enyne Metathesis/Cross Metathesis Reaction to the Total Synthesis of (+)-8-epi-Xanthatin. Org Lett 2005; 7:4621-3. [PMID: 16209494 DOI: 10.1021/ol051711a] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The first total synthesis of the novel sesquiterpene lactone (+)-8-epi-xanthatin (1) has been achieved starting from the commercially available ester 8. The synthesis features an asymmetric aldol reaction and palladium-catalyzed carbonylation/lactonization sequence leading to 4 and a domino ring-closing enyne metathesis/cross metathesis reaction to afford 1.
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