@article {2491, title = {The Direct Synthesis of Unsymmetrical Vicinal Diamines from Terminal Alkynes: A Tandem Sequential Approach for the Synthesis of Imidazolidinones}, journal = {Synthesis-Stuttgart}, number = {1}, year = {2009}, note = {ISI Document Delivery No.: 395LSTimes Cited: 6Cited Reference Count: 84Lee, Alison V. Sajitz, Melanie Schafer, Laurel L.Sp. Iss. SI}, month = {Jan}, pages = {97-104}, type = {Article}, abstract = {The combination of titanium-catalyzed anti-Markovnikov hydroamination of terminal alkynes with the Strecker reaction is used in the synthesis of unsymmetrical vicinal diamines via the one-pot synthesis of alpha-cyanoamines. This methodology is Further applied to the efficient synthesis of imidazolidinones. An easy-to-use bis(amidate)titanium precatalyst permits efficient approaches to heterocyclic chemistry from terminal alkynes.}, keywords = {AMINES, ANTI-MARKOVNIKOV, ASYMMETRIC-SYNTHESIS, CATALYZED INTERMOLECULAR HYDROAMINATION, HETEROCYCLES, HYDROAMINATION, IMIDO COMPLEXES, INTRAMOLECULAR HYDROAMINATION, LIGANDS, SCOPE, tandem reactions, TITANIUM, TITANIUM PRECATALYST, VINYLARENES}, isbn = {0039-7881}, url = {://000262526200012}, author = {Lee, A. V. and Sajitz, M. and Schafer, L. L.} } @article {2107, title = {Synthetic studies toward halichlorine: Complex azaspirocycle formation with use of an NBS-promoted semipinacol reaction}, journal = {Journal of Organic Chemistry}, volume = {73}, number = {11}, year = {2008}, note = {ISI Document Delivery No.: 307MRTimes Cited: 13Cited Reference Count: 90Hurley, Paul B. Dake, Gregory R.}, month = {Jun}, pages = {4131-4138}, type = {Article}, abstract = {The investigations of a synthetic route incorporating a NIBS-promoted semipinacol rearrangement to the 6-azaspiro[4.5]decane fragment within halichlorine (1) are presented. A convergent approach was pursued, utilizing two chiral, enantiomerically enriched building blocks, 2-trimethylstannyl piperidene 10 and substituted cyclobutanone 19. Noteworthy synthetic operations in this study include the following: (a) a highly diastereoselective NBS-promoted semipinacol reaction that established four stereogenic centers in ketone 25 and (b) the use of a N-p-toluenesulfonyl-2-iodo-2-piperidene as a precursor to a basic organometallic reagent, which was critical to the success of the coupling of fragments 10 and 19.}, keywords = {(+/-)-PINNAIC ACID, ASYMMETRIC-SYNTHESIS, BAEYER-VILLIGER OXIDATION, CARBOXYLIC-ACIDS, CRIEGEE REARRANGEMENT, ETHYLMAGNESIUM BROMIDE, ORGANIC-SYNTHESIS, PINNAIC ACID, RING-CLOSING METATHESIS, SPIROCYCLIC CORE}, isbn = {0022-3263}, url = {://000256323500018}, author = {Hurley, P. B. and Dake, G. R.} } @article {829, title = {Investigations of alpha-siloxy-epoxide ring expansions forming 1-azaspirocyclic ketones}, journal = {Journal of Organic Chemistry}, volume = {69}, number = {17}, year = {2004}, note = {ISI Document Delivery No.: 845XHTimes Cited: 13Cited Reference Count: 97}, month = {Aug}, pages = {5676-5683}, type = {Article}, abstract = {The construction of 1-azaspirocyclic cycloalkanones using a siloxy-epoxide semipinacol ring expansion process was examined. Functionalized 1-azaspiro[5.5]undecan-7-ones (1-azaspirocyclic cyclohexanones) proceeded in high chemical yields with complete diastereoselectivity using titanium tetrachloride as the Lewis acid promoter. The formation of functionalized 6-azaspiro[5.4]-decan-1-ones (1-azaspirocyclic cyclopentanones) proceeded in high chemical yield with little diastereoselectivity. Modification of reaction parameters such as the Lewis acid promoter or the nature of the silyl ether allowed for the preferential formation of either ("anti" or "syn" 1,2 alkyl shift) diastereomeric product. An explanation for the different reactivity profiles between the cyclobutanol silyl ethers and cyclopentanol silyl ethers is provided.}, keywords = {1ST TOTAL-SYNTHESIS, ALDOL ALDOL PROCESS, ASYMMETRIC-SYNTHESIS, BAEYER-VILLIGER OXIDATION, LEWIS-ACIDS, ORGANIC-SYNTHESIS, PRACTICAL, QUATERNARY CARBON CENTERS, REARRANGEMENT, SEMI-PINACOL, SILYL ETHER REARRANGEMENTS, STEREOSELECTIVE CONSTRUCTION}, isbn = {0022-3263}, url = {://000223278200021}, author = {Dake, G. R. and Fenster, M. D. B. and Fleury, M. and Patrick, B. O.} } @article {701, title = {Synthesis and antimitotic/cytotoxic activity of hemiasterlin analogues}, journal = {Journal of Natural Products}, volume = {66}, number = {2}, year = {2003}, note = {ISI Document Delivery No.: 652JHTimes Cited: 45Cited Reference Count: 37}, month = {Feb}, pages = {183-199}, type = {Article}, abstract = {The antimitotic sponge tripeptide hemiasterlin (1) and a number of structural analogues have been synthesized and evaluated in cell-based assays for both cytotoxic and antimitotic activity in order to explore the SAR for this promising anticancer drug lead. One synthetic analogue, SPA110 (8), showed more potent in vitro cytotoxicty and antimitotic activity than the natural product hemiasterlin (1), and consequently it has been subjected to thorough preclinical evaluation and targeted for clinical evaluation. The details of the synthesis of hemiasterlin (1) and the analogues and a discussion of how their biological activities vary with their structures are presented in this paper.}, keywords = {(-)-HEMIASTERLIN, AGENTS, ALPHA-AMINO-ACIDS, ASYMMETRIC-SYNTHESIS, AZIDATION, CYTOTOXIC PEPTIDES, ELEUTHEROBIN, TRIPEPTIDE, TUBULIN}, isbn = {0163-3864}, url = {://000181375700005}, author = {Nieman, J. A. and Coleman, J. E. and Wallace, D. J. and Piers, E. and Lim, L. Y. and Roberge, M. and Andersen, R. J.} } @article {4054, title = {Determination of the absolute steric course of are enantioselective single crystal-to-single crystal photorearrangement}, journal = {Journal of the American Chemical Society}, volume = {119}, number = {6}, year = {1997}, note = {ISI Document Delivery No.: WH326Times Cited: 27Cited Reference Count: 25}, month = {Feb}, pages = {1462-1463}, type = {Article}, keywords = {ASYMMETRIC-SYNTHESIS, PHOTOCHEMISTRY, PHOTODIMERIZATION, SOLID-STATE POLYMERIZATION}, isbn = {0002-7863}, url = {://A1997WH32600039}, author = {Leibovitch, M. and Olovsson, G. and Scheffer, J. R. and Trotter, J.} } @article {4054, title = {Determination of the absolute steric course of are enantioselective single crystal-to-single crystal photorearrangement}, journal = {Journal of the American Chemical Society}, volume = {119}, number = {6}, year = {1997}, note = {ISI Document Delivery No.: WH326Times Cited: 27Cited Reference Count: 25}, month = {Feb}, pages = {1462-1463}, type = {Article}, keywords = {ASYMMETRIC-SYNTHESIS, PHOTOCHEMISTRY, PHOTODIMERIZATION, SOLID-STATE POLYMERIZATION}, isbn = {0002-7863}, url = {://A1997WH32600039}, author = {Leibovitch, M. and Olovsson, G. and Scheffer, J. R. and Trotter, J.} } @article {3874, title = {Total synthesis of (-)-hemiasterlin, a structurally novel tripeptide that exhibits potent cytotoxic activity}, journal = {Tetrahedron Letters}, volume = {38}, number = {3}, year = {1997}, note = {ISI Document Delivery No.: WC807Times Cited: 44Cited Reference Count: 16}, month = {Jan}, pages = {317-320}, type = {Article}, abstract = {The total synthesis of (-)-hemiasterlin (2), a structurally novel, naturally occurring tripeptide that exhibits potent cytotoxic and antimitotic activity against human breast cancer MCF7 cells, is described. Copyright (C) 1996 Elsevier Science Ltd}, keywords = {ALPHA-AMINO-ACIDS, ASYMMETRIC-SYNTHESIS, AZIDATION, PEPTIDES}, isbn = {0040-4039}, url = {://A1997WC80700005}, author = {Andersen, R. J. and Coleman, J. E. and Piers, E. and Wallace, D. J.} } @article {3264, title = {THE ONE-STEP SYNTHESIS OF CHIRAL AMINO PHOSPHINO FERROCENES}, journal = {Journal of Organometallic Chemistry}, volume = {492}, number = {2}, year = {1995}, note = {ISI Document Delivery No.: QV350Times Cited: 10Cited Reference Count: 24}, month = {May}, pages = {157-164}, type = {Article}, abstract = {Reaction of the chiral lithium reagent-2-lithio-(alpha-N,N-dimethyl)aminoethylbenzene with 1,1{\textquoteright}-ferrocenediylphenylphosphine gives chiral aminophosphinoferrocenes that contain both chiral carbon and phosphorus centres. Treatment of the ferroceno-phane with 2-lithio-N,N-dimethylaminomethylferrocene followed by hydrolysis gives the product ferrocenyl 2-(dimethylaminomethylferrocenyl) phenylphosphine as a pair of diastereomers. The single crystal structures of compound 3a PdCl2 and compound 4. PdCl2.2CH(2)Cl(2) have been determined. The compounds, 2-(ferrocenylphenylphosphino)-1-(alpha-N, N{\textquoteright}-dimethylaminoethylbenzene)ferrocene, 5 and 1-[2-(alpha-N,N{\textquoteright}-dimethyraminoethylbenzene)phenylphospphino]-1{\textquoteright}-diphenyl phosphinoferrocene, 6a, have also been prepared by minor modifications of the methodology developed.}, keywords = {<1>FERROCENOPHANES, ASYMMETRIC-SYNTHESIS, CATALYST, chirality, crystal structure, FERROCENE, GRIGNARD, HALIDES, HYDROGENATION, iron, METAL-COMPLEXES, ORGANIC, palladium, PHOSPHORUS, PLANAR CHIRALITY, REAGENTS, SECONDARY}, isbn = {0022-328X}, url = {://A1995QV35000005}, author = {Butler, I. R. and Cullen, W. R. and Rettig, S. J. and White, A. S. C.} } @article {3034, title = {THE SYNTHESIS OF ANTHRAPHOS, A CONFORMATIONALLY RIGID, C-2-SYMMETRICAL DIPHOSPHINE AND THE X-RAY CRYSTAL-STRUCTURE OF [RH(COD)(ANTHRAPHOS)]BF4}, journal = {Tetrahedron Letters}, volume = {35}, number = {41}, year = {1994}, note = {ISI Document Delivery No.: PL496Times Cited: 7Cited Reference Count: 18}, month = {Oct}, pages = {7593-7596}, type = {Article}, abstract = {Anthraphos (trans-9,10-dihydro-9,10-ethanoanthracene-11,12-bis(diphenylphosphine) (3), a conformationally rigid, C-2-symmetric diphosphine, has been prepared in three steps, the key step being the Diets-Alder reaction between anthracene and ethyndiylbis(diphenylphosphine oxide). Resolution of anthraphos followed by formation of the [Rh(COD)(anthraphos)]BF4 complex afforded an optically active hydrogenation catalyst precursor whose crystal and molecular structure and absolute configuration were determined by single crystal X-ray diffractometry. Use of the (R,R)-(-) form of the catalyst precursor to hydrogenate (Z)-alpha-acetamidocinnamic acid gave (S)-(+)-N-acetylphenylalanine in 90\% enantiomeric excess.}, keywords = {ACID, ASYMMETRIC-SYNTHESIS, COMPLEXES, HYDROGENATION, LIGANDS, NORPHOS}, isbn = {0040-4039}, url = {://A1994PL49600027}, author = {Fu, T. Y. and Liu, Z. Q. and Scheffer, J. R. and Trotter, J.} } @article {3034, title = {THE SYNTHESIS OF ANTHRAPHOS, A CONFORMATIONALLY RIGID, C-2-SYMMETRICAL DIPHOSPHINE AND THE X-RAY CRYSTAL-STRUCTURE OF [RH(COD)(ANTHRAPHOS)]BF4}, journal = {Tetrahedron Letters}, volume = {35}, number = {41}, year = {1994}, note = {ISI Document Delivery No.: PL496Times Cited: 7Cited Reference Count: 18}, month = {Oct}, pages = {7593-7596}, type = {Article}, abstract = {Anthraphos (trans-9,10-dihydro-9,10-ethanoanthracene-11,12-bis(diphenylphosphine) (3), a conformationally rigid, C-2-symmetric diphosphine, has been prepared in three steps, the key step being the Diets-Alder reaction between anthracene and ethyndiylbis(diphenylphosphine oxide). Resolution of anthraphos followed by formation of the [Rh(COD)(anthraphos)]BF4 complex afforded an optically active hydrogenation catalyst precursor whose crystal and molecular structure and absolute configuration were determined by single crystal X-ray diffractometry. Use of the (R,R)-(-) form of the catalyst precursor to hydrogenate (Z)-alpha-acetamidocinnamic acid gave (S)-(+)-N-acetylphenylalanine in 90\% enantiomeric excess.}, keywords = {ACID, ASYMMETRIC-SYNTHESIS, COMPLEXES, HYDROGENATION, LIGANDS, NORPHOS}, isbn = {0040-4039}, url = {://A1994PL49600027}, author = {Fu, T. Y. and Liu, Z. Q. and Scheffer, J. R. and Trotter, J.} }