The Conservation of Orbital Symmetry

The study of biomolecules in their native environments is a challenging task because of the vast complexity of cellular systems. Technologies developed in the last few years for the selective modification of biological species in living systems have yielded new insights into cellular processes. Key to these new techniques are bioorthogonal chemical reactions, whose components must react rapidly and selectively with each other under physiological conditions in the presence of the plethora of functionality necessary to sustain life. Herein we describe the bioorthogonal chemical reactions developed to date and how they can be used to study biomolecules.

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Bioorthogonal Chemistry: Fishing for Selectivity in a Sea of Functionality

In contrast to the very large number of special methods applicable to syntheses in the heterocyclic series, relatively few general methods are available. The 1,3-dipolar addition offers a remarkably wide range of utility in the synthesis of five-membered heterocycles. Here the “1,3-dipole”, which can only be represented by zwitterionic octet resonance structures, combines in a cycloaddition with a multiple bond system – the “dipolarophile” – to form an uncharged five-membered ring. Although numerous individual examples of this reaction were known, some even back in the nineteenth century, fruitful development of this synthetic principle has been achieved only in recent years.

1,3-Dipolar Cycloadditions. Past and Future†

The new ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) approach has been proposed and shown to be successful in reproducing benchmark calculations and experimental results. ONIOM3, a three-layered version, divides a system into an active part treated at a very high level of ab initio molecular orbital theory like CCSD(T), a semiactive part that includes important electronic contributions and is treated at the HF or MP2 level, and a nonactive part that is handled using force field approaches. The three-layered scheme allows us to study a larger system more accurately than the previously proposed two-layered schemes IMOMO, which can treat a medium size system very accurately, and IMOMM, which can handle a very large system with modest accuracy. This three-layered scheme has been applied to activation barriers for the Diels−Alder reaction of acrolein + isoprene, acrolein + 2-tert-butyl-1,3-butadiene, and ethylene + 1,4-di-tert-butyl-1,3-butadiene. In general, the results for b...

ONIOM: A Multilayered Integrated MO + MM Method for Geometry Optimizations and Single Point Energy Predictions. A Test for Diels−Alder Reactions and Pt(P(t-Bu)3)2 + H2 Oxidative Addition

Asymmetric 1,3-Dipolar Cycloaddition Reactions

Synthesen in der hydroaromatischen Reihe

Untersuchungen über den Verlauf der Diensynthese

Über die Anlagerung von Maleinsäure‐anhydrid und Azodicarbonsäure‐ester an einfach ungesättigte Koh an einfach ungesättigte Kohlenwasserstoffe. Zur Kenntnis von Substitutionsvorgängen in der Allyl‐Stellung

Synthesen in der hydro-aromatischen Reihe, II. Mitteilung: Über Cantharidin

Synthesen in der hydroaromatischen Reihe. III. Mitteilung: Synthese von Terpenen, Camphern, hydroaromatischen und heterocyclischen Systemen. Mitbearbeitet von den Herren Wolfgang Lübbert, Erich Naujoks, Franz Querberitz, Karl Röhl, Harro Segeberg

Kurt Alder

Papers

Synthesen in der hydroaromatischen Reihe

Untersuchungen über den Verlauf der Diensynthese

Über die Anlagerung von Maleinsäure‐anhydrid und Azodicarbonsäure‐ester an einfach ungesättigte Koh an einfach ungesättigte Kohlenwasserstoffe. Zur Kenntnis von Substitutionsvorgängen in der Allyl‐Stellung

Synthesen in der hydro-aromatischen Reihe, II. Mitteilung: Über Cantharidin

Synthesen in der hydroaromatischen Reihe. III. Mitteilung: Synthese von Terpenen, Camphern, hydroaromatischen und heterocyclischen Systemen. Mitbearbeitet von den Herren Wolfgang Lübbert, Erich Naujoks, Franz Querberitz, Karl Röhl, Harro Segeberg