@inbook {1243, title = {Asymmetric induction in organic photochemistry via the solid-state ionic chiral auxiliary approach}, booktitle = {Organic Solid State Reactions}, series = {Topics in Current Chemistry}, volume = {254}, year = {2005}, note = {ISI Document Delivery No.: BCP68Times Cited: 29Cited Reference Count: 57ReviewHEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY}, pages = {233-262}, publisher = {Springer-Verlag Berlin}, organization = {Springer-Verlag Berlin}, address = {Berlin}, abstract = {After a brief introduction and summary of various methods of asymmetric induction in organic photochemistry, the main part of the review covers the solid-state ionic chiral auxiliary approach to asymmetric photochemical synthesis. Application of this technique to the Norrish type II reaction, as well as to the di-Ti-methane and oxa-di-pi-methane photorearrangements, and the Cis, trans-photoisomerization of diarylcyclopropane derivatives is presented and discussed.}, keywords = {ABSOLUTE-CONFIGURATION, ACHIRAL, AMMONIUM CARBOXYLATE SALTS, ASYMMETRIC INDUCTION, auxiliaries, crystal structure-reactivity correlations, CRYSTALLINE STATE, di-pi-methane, ionic chiral, MODIFIED ZEOLITES, MOLECULES, organic photochemistry, PHOTOCYCLIZATION, SINGLE-CRYSTALS, solid state, STRUCTURE-REACTIVITY RELATIONSHIPS, TROPOLONE ETHER}, isbn = {0340-1022}, url = {://000230596800007}, author = {Scheffer, J. R. and Xia, W. J.} } @article {727, title = {The photochemistry of trans-1,4,4,4-tetraphenylbut-2-en-1-one: A highly efficient aryl migration (type B) enone photorearrangement}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {81}, number = {6}, year = {2003}, note = {ISI Document Delivery No.: 706UATimes Cited: 0Cited Reference Count: 18}, month = {Jun}, pages = {705-708}, type = {Article}, abstract = {Photolysis of trans-1,4,4,4-tetraphenylbut-2-en-1-one (3) in acetonitrile or benzene leads to trans-cis isomerization (7) along with rearrangement to trans-1 -benzoyl-2,2,3-triphenylcyclopropane(8). Formation of the latter product represents a new example of the aryl migration (type B) enone photorearrangement reaction first reported by Zimmerman and co-workers for 4,4-diphenylcyclohex-2-en-1-one (1). The quantum yield in the case of enone 3 (0.4) is approximately 10 times greater than that for 4,4,-diphenylcyclohex-2-en-1-one, a result that is ascribed to steric acceleration of phenyl migration from the triphenylmethyl group plus greater resonance stabilization of the intermediate biradical.}, keywords = {aryl migration, ASYMMETRIC INDUCTION, di-pi-methane, enone, EXPLORATORY ORGANIC PHOTOCHEMISTRY, MECHANISM, MIGRATION, PHENYL, PHOTOCHEMISTRY, PHOTOCYCLIZATION, REARRANGEMENT, STATE}, isbn = {0008-4042}, url = {://000184472400035}, author = {Scheffer, J. R. and Vishnumurthy, K.} } @article {5185, title = {2000 Alfred Bader Award Lecture - In the footsteps of Pasteur: asymmetric induction in the photochemistry of crystalline ammonium carboxylate salts}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {79}, number = {4}, year = {2001}, note = {ISI Document Delivery No.: 429PNTimes Cited: 51Cited Reference Count: 52}, month = {Apr}, pages = {349-357}, type = {Article}, abstract = {This review describes the development of a new, synthetically useful method of asymmetric synthesis in organic photochemistry. Similar in many ways to the Pasteur procedure for resolving racemic carboxylic acids and organic amines, the method relies on the use of crystalline organic salts in which the enantioselectivity of a photochemical reaction of an achiral organic ion (for example, a carboxylate anion) is governed in the solid state by the presence of an optically pure counterion (for example, an optically active ammonium ion). Such optically pure counterions are termed ionic chiral auxiliaries. Salts containing ionic chiral auxiliaries are required to crystallize in chiral space groups, which provide the asymmetric environment necessary for chiral induction. Using this methodology, we have obtained near-quantitative optical yields in a wide variety of photochemical reactions.}, keywords = {ABSOLUTE-CONFIGURATION CORRELATION, ACID-DERIVATIVES, asymmetric synthesis, chiral auxiliaries, crystal structure-reactivity relationships, di-pi-methane, GEOMETRIC REQUIREMENTS, II REACTION, ionic chiral auxiliaries, ORGANIC-PHOTOCHEMISTRY, PHOTOCHEMISTRY, solid state, SOLID-STATE PHOTOCHEMISTRY, STRUCTURE-REACTIVITY RELATIONSHIPS, YANG PHOTOCYCLIZATION REACTION}, isbn = {0008-4042}, url = {://000168526300001}, author = {Scheffer, J. R.} } @article {4576, title = {The use of ionic chiral sensitizers in the crystalline state: application to the di-pi-methane photorearrangement of a benzonorbornadiene derivative}, journal = {Tetrahedron Letters}, volume = {40}, number = {50}, year = {1999}, note = {ISI Document Delivery No.: 258FJTimes Cited: 8Cited Reference Count: 15}, month = {Dec}, pages = {8725-8728}, type = {Article}, abstract = {Simultaneous asymmetric induction and triplet-triplet energy transfer has been achieved in the di-pi-methane photorearrangement of a benzonorbornadiene derivative through the use of {\textquoteright}ionic chiral sensitizers{\textquoteright}. In this approach, salts formed between a reactant carboxylic acid and optically pure sensitizer amines are irradiated and the products monitored for optical activity following removal of the ionic auxiliary. In contrast to the results in solution, where only racemic products are formed, photolysis of the salts in the crystalline state leads to enantiomeric excesses as high as 91\% at 100\% conversion. (C) 1999 Elsevier Science Ltd. All rights reserved.}, keywords = {ammonium salts, ASYMMETRIC INDUCTION, di-pi-methane, PHOTOCHEMISTRY, REARRANGEMENT}, isbn = {0040-4039}, url = {://000083827200002}, author = {Janz, K. M. and Scheffer, J. R.} } @article {7194, title = {DIFFERENCES IN PHOTOCHEMICAL REACTIVITY OF 9,10-ETHENOANTHRACENE DERIVATIVES IN LIQUID AND CRYSTALLINE MEDIA}, journal = {Tetrahedron}, volume = {48}, number = {16}, year = {1992}, note = {ISI Document Delivery No.: HP785Times Cited: 28Cited Reference Count: 66}, month = {Apr}, pages = {3251-3274}, type = {Article}, keywords = {ABSOLUTE ASYMMETRIC-SYNTHESIS, ACHIRAL REACTANTS, CHIRAL SINGLE-CRYSTALS, CONVERT, di-pi-methane, HIGH OPTICAL YIELD, II PHOTOREARRANGEMENTS, ORGANIC-CHEMISTRY, PHOTO-POLYMERIZATION, QUANTITATIVE ENANTIOMERIC YIELD, SOLID-STATE PHOTOCHEMISTRY}, isbn = {0040-4020}, url = {://A1992HP78500001}, author = {Chen, J. X. and Scheffer, J. R. and Trotter, J.} } @article {7194, title = {DIFFERENCES IN PHOTOCHEMICAL REACTIVITY OF 9,10-ETHENOANTHRACENE DERIVATIVES IN LIQUID AND CRYSTALLINE MEDIA}, journal = {Tetrahedron}, volume = {48}, number = {16}, year = {1992}, note = {ISI Document Delivery No.: HP785Times Cited: 28Cited Reference Count: 66}, month = {Apr}, pages = {3251-3274}, type = {Article}, keywords = {ABSOLUTE ASYMMETRIC-SYNTHESIS, ACHIRAL REACTANTS, CHIRAL SINGLE-CRYSTALS, CONVERT, di-pi-methane, HIGH OPTICAL YIELD, II PHOTOREARRANGEMENTS, ORGANIC-CHEMISTRY, PHOTO-POLYMERIZATION, QUANTITATIVE ENANTIOMERIC YIELD, SOLID-STATE PHOTOCHEMISTRY}, isbn = {0040-4020}, url = {://A1992HP78500001}, author = {Chen, J. X. and Scheffer, J. R. and Trotter, J.} }