Unlimited non-linear selectivity effects in systems of independent parallel reactions as a basis for new chemical separation techniques

Brandt, Josef; Jochum, Clemens; Ugi, Ivar; Jochum, Peter

doi:10.1016/0040-4020(77)84085-4

Cited by 55 publications

(23 citation statements)

References 19 publications

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“…This has lead to a new strategy termed parallel kinetic resolution [3] (PKR; Scheme 1). The concept of such a strategy is not new, in fact, the theoretical data [4] have been available for many years. It has been shown that the selectivity factor s can be significantly lower for a parallel resolution than for a traditional kinetic resolution to acheive the same result.…”

mentioning

confidence: 99%

“…[5] Treatment of (rac)-1 with the catalyst tetrakis(4S-methoxycarbonyl-2-oxyoxazolidinyl)dirhodium(ii) ([Rh 2 (4S-MEOX) 4 ], (S)-2) gave the tricyclic ketone (1S,2R,6S)-3 in 40 % yield with an enantiomeric excess of 94 %. Surprisingly, the fate of the other enantiomer (R)-1 is accounted for by the by-product 2-cyclohexenone (4), which was formed by intramolecular hydride abstraction with subsequent ketene loss.…”

mentioning

confidence: 99%

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Parallel Kinetic Resolutions

Eames

2000

Angew. Chem. Int. Ed.

115

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confidence: 99%

mentioning

confidence: 99%

Parallel Kinetic Resolutions

Eames

2000

Angew. Chem. Int. Ed.

115

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“…Figure 4 presents a plot of the maximum yield of initial products of a specific minimum se as a function of the selectivity.14 Significantly, processes with selectivities of 3.2, 4.3, 5.3, and 6.6 are calculated to give a 50% yield of products with an se of 80%, 90%, 95%, and 98%, respectively. 16 The potential of this type of process to enhance the stereoiso-0.40 0.30 0.20 0.10-I6These cases approach the result from a hypothetical nonstereoselective reaction (100% yield) followed by separation of the stereoisomeric products. By contrast, these cases would require the separation of nonisomeric compounds (i.e., P and B).…”

Section: Figmentioning

confidence: 99%

“…In this case, however, the interactions are heteromorphic (i.e., P and Q) and, in principle, will be of different energy and occur with unequal p r~b a b i l i t~.~ A kinetically controlled reaction involving the differentiation of enantiotopic facess or enantiotopic groups where sequential reaction is prevented9 (e.g., eq. [I]) can be analyzed as a pair of mutually dependent parallel reactions (16). The ratio of products P and Q (i.e., the selectivity) is equal to the ratio of rate constants kl and kz at any point in the reaction.''…”

Section: Background and Theorymentioning

confidence: 99%

Asymmetric synthesis using reactions with modest group selectivity

Ward¹,

Liu²,

Rhee³

1994

Can. J. Chem.

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The isomeric purity of products from certain group-selective reactions can be significantly amplified when reactib:~:; can occur sequentially. The theoretical basis for a strategy that exploits reactions with modest enantiotopic group selectivity for asymmetric synthesis is described. The relationships between conversion, yield, and isomeric purity for such a process are calculated using a simple kinetic model. A simple method for selecting candidate group-selective reactions from known face-selective reactions is presented. Application of the strategy is illustrated with the reduction of D-glucose and D-galactose derived dialdehydes with B-isopinocampheyl-9-borabicyclo[3.3.1]nonane (~l~i n e -B o r a n e B ) . DALE E. WARD, YADONC LIU et CHUNC K. RHEE. Can. J. Chem. 72, 1429Chem. 72, (1994.On peut grandement amCliorer la puretC isomtrique des produits de certaines rCactions sClectives pour des groupes si l'on effectue ces rkactions d'une f a~o n ~Cquentielle. On dCcrit les bases thkoriques d'une stratkgie qui exploite des rkactions possCdant de modestes sClectivitCs Cnantiotopiques pour des groupes B des fins de synthbses asymitriques. Faisant appel B un modble cinktique simple, on peut calculer facilement les relations entre la conversion, le rendement et la puretC isomCrique de tels processus. On prCsente une mtthode simple permettant de choisir les rCactions plausibles pour leur sClectivitC pour des groupes B partir de rkactions connues pour leur sClectivitC pour les faces. On illustre l'application de la stratCgie B la rCduction des dialdthydes dCrivCs du D-glucose et du D-galactose par le B-isopinocamphCyl-9-borabicyclo[3.3.l]nonane (~l~i n e -B o r a n e B ) .[Traduit par la RCdaction] IntroductionThe development of methods for the synthesis of enantiomerically pure compounds has attracted considerable attention from synthetic organic chemists in recent years (1-3). In particular, significant advances have been achieved in the enantioselective conversion of achiral substrates into chiral products (1-3). Such transformations require a process where enantiotopic (4) faces or groups in the substrate are differentiated (5). This type of differentiation is possible since enantiotopic relationships become diastereotopic in the dissymmetric environment provided by a chiral reagent, auxiliary, solvent, additive, or catalyst (including enzymes (6) and abzymes (7)). While many methods that achieve high levels of enantiotopic face selectivity have been developed (1-3), nonenzymatic2 examples of efficient enantiotopic group selectivity are less common (8).An interesting feature of certain processes where enantiotopic groups can react sequentially is the coupling of an asymmetric synthesis with a kinetic resolution (9) to produce products with enhanced levels of enantiomeric p~r i t y .~ Sih and co-workers (IOU, b) explicitly demonstrated the viability of this approach in the enzyme-catalyzed hydrolysis of meso diacetates. Bosnich and co-workers (1 1) pointed out that enhanced enantiomeric purity by kinetic resoluti...

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“…[3] Das Konzept dieser Strategie ist eigentlich nicht neu. So gibt es bereits seit Jahren theoretische Daten, [4] denen zufolge eine parallele kinetische Enantiomerentrennung zum gleichen Ergebnis führt wie eine herkömmliche kinetische Enantiomerentrennung, allerdings bei einem deutlich niedrigeren Selektivitätsfaktor s. So entspricht s 49 in der PKR einem Selektivitätsfaktor von 200 in der herkömmlichen Variante, in der die Produkte in 49 % Ausbeute (ausgehend von 50 %) und mit 96 % ee isoliert werden.…”

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Parallele kinetische Enantiomerentrennungen

Eames

2000

Angewandte Chemie

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Unlimited non-linear selectivity effects in systems of independent parallel reactions as a basis for new chemical separation techniques

Cited by 55 publications

References 19 publications

Parallel Kinetic Resolutions

Parallel Kinetic Resolutions

Asymmetric synthesis using reactions with modest group selectivity

Parallele kinetische Enantiomerentrennungen

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