VI
Preface
organize a symposium on ‘Organocatalysis,’ which took place in Berlin,
Germany, from 18 to 20 April 2007. The proceedings of this symposium
are detailed in this book.
S.C. Pan and B. List’s paper spans the whole field of current organocatalysts discussing Lewis and Brønsted basic and acidic catalysts. Starting from the development of proline-mediated enamine catalysis—
the Hajos–Parrish–Eder–Sauer–Wiechert reaction is an intramolecular
transformation involving enamine catalysis—into an intermolecular process with various electrophilic reaction partners as a means to access
α-functionalized aldehydes, they discuss a straightforward classification of organocatalysts and expands on Brønsted acid-mediated transformations, and describe the development of asymmetric counteraniondirected catalysis (ACDC).
Impressive applications of chiral amine organocatalysts in natural
product synthesis come from the D. Enders’ laboratory. Enders and colleagues elegantly employ the different modes of enamine and iminium
activation in domino reactions leading to highly functionalized cyclohexenes. Using dihydroxyacetone acetonide the amine organocatalyst
functions like an artificial aldolase eventually leading to carbohydrates,
sphingolipids, and carbasugars. In the following chapter, M. Christmann
reports examples for organocatalytic key steps in the total synthesis of
the terpene alkaloid and telomerase inhibitor UCS1025A.
More examples for ‘applied organocatalysis’ are presented by
H. Gröger, who gives an overview of organocatalytic methods already
applied on a technical scale. Based on case studies, he shows several
examples that satisfy the criteria of a technically feasible process such
as high catalyst activity and stability, economic access, sustainability,
atom economy, and high volumetric productivity.
Another privileged class of Lewis basic organocatalysts are nucleophilic carbenes, which have been proven to be extremely versatile
for different transformation, albeit strongly depending on the electronic and steric nature of the catalyst. F. Glorius and K. Hirano apply N-heterocyclic carbenes (NHC) for a conjugate umpolung of α,βunsaturated aldehydes into homoenolates, which are then reacted with
aldehydes or ketones to γ -butyrolactones or β-lactones. A review on
N-heterocyclic carbenes as a class of organocatalysts beyond the well-
Preface
organize a symposium on ‘Organocatalysis,’ which took place in Berlin,
Germany, from 18 to 20 April 2007. The proceedings of this symposium
are detailed in this book.
S.C. Pan and B. List’s paper spans the whole field of current organocatalysts discussing Lewis and Brønsted basic and acidic catalysts. Starting from the development of proline-mediated enamine catalysis—
the Hajos–Parrish–Eder–Sauer–Wiechert reaction is an intramolecular
transformation involving enamine catalysis—into an intermolecular process with various electrophilic reaction partners as a means to access
α-functionalized aldehydes, they discuss a straightforward classification of organocatalysts and expands on Brønsted acid-mediated transformations, and describe the development of asymmetric counteraniondirected catalysis (ACDC).
Impressive applications of chiral amine organocatalysts in natural
product synthesis come from the D. Enders’ laboratory. Enders and colleagues elegantly employ the different modes of enamine and iminium
activation in domino reactions leading to highly functionalized cyclohexenes. Using dihydroxyacetone acetonide the amine organocatalyst
functions like an artificial aldolase eventually leading to carbohydrates,
sphingolipids, and carbasugars. In the following chapter, M. Christmann
reports examples for organocatalytic key steps in the total synthesis of
the terpene alkaloid and telomerase inhibitor UCS1025A.
More examples for ‘applied organocatalysis’ are presented by
H. Gröger, who gives an overview of organocatalytic methods already
applied on a technical scale. Based on case studies, he shows several
examples that satisfy the criteria of a technically feasible process such
as high catalyst activity and stability, economic access, sustainability,
atom economy, and high volumetric productivity.
Another privileged class of Lewis basic organocatalysts are nucleophilic carbenes, which have been proven to be extremely versatile
for different transformation, albeit strongly depending on the electronic and steric nature of the catalyst. F. Glorius and K. Hirano apply N-heterocyclic carbenes (NHC) for a conjugate umpolung of α,βunsaturated aldehydes into homoenolates, which are then reacted with
aldehydes or ketones to γ -butyrolactones or β-lactones. A review on
N-heterocyclic carbenes as a class of organocatalysts beyond the well-