Cascade Processes of Metallo Carbenoids

Transition-metal catalyzed decomposition of aliphatic diazo compounds — New results and applications in organic synthesis

Natural and synthetic 2H-pyran-2-ones and their versatility in organic synthesis☆

We report that chiral bicyclic guanidine 1 is found to catalyze the isomerization of alkynes to chiral allenes with high enantioselectivities. This Bronsted base catalyzed 1,3-proton shift reaction, an efficient and atom economical reaction, proceeds through deprotonation and protonation sequences. The axial chirality of the allenes is efficiently transferred to functionalized butenolides and cycloaddition products. We also successfully demonstrate the stereospecific synthesis of butenolide through allenoate cyclization with a catalytic cationic Au(I) complex.

Enantioselective Synthesis of Chiral Allenoates by Guanidine-Catalyzed Isomerization of 3-Alkynoates

Catalysis and synthesis are intimately linked in modern organic chemistry. The synthesis of complex molecules is an ever evolving area of science. In many regards, the inherent beauty associated with a synthetic sequence can be linked to a certain combination of the creativity with which a sequence is designed and the overall efficiency with which the ultimate process is performed. In synthesis, as in other endeavors, beauty is very much in the eyes of the beholder.† It is with this in mind that we will attempt to review an area of synthesis that has fascinated us and that we find extraordinarily beautiful, namely the combination of catalysis and sigmatropic rearrangements in consecutive and cascade sequences.

Toward a Symphony of Reactivity: Cascades Involving Catalysis and Sigmatropic Rearrangements

The reactivity of 4-hydroxy-6-methyl-2-pyrone towards aliphatic saturated and α,β-unsaturated aldehydes

Reactions between 4‐hydroxy‐6‐methyl‐2‐pyrone and aldehydes both in the absence and the presence of added thiols

Brominated derivatives of 4‐hydroxy‐ and 4‐methoxy‐6‐methyl‐2H‐pyran‐2‐ones

The reactivity of 4‐hydroxy‐6‐methyl‐2‐pyrone towards different types of ketones

The reactions of 4‐hydroxy‐2‐pyrones with 2‐hydroxybenzaldehydes. A note of warning

P. De March

Papers

The reactivity of 4-hydroxy-6-methyl-2-pyrone towards aliphatic saturated and α,β-unsaturated aldehydes

Reactions between 4‐hydroxy‐6‐methyl‐2‐pyrone and aldehydes both in the absence and the presence of added thiols

Brominated derivatives of 4‐hydroxy‐ and 4‐methoxy‐6‐methyl‐2H‐pyran‐2‐ones

The reactivity of 4‐hydroxy‐6‐methyl‐2‐pyrone towards different types of ketones

The reactions of 4‐hydroxy‐2‐pyrones with 2‐hydroxybenzaldehydes. A note of warning