10. Patented Literature 2616 10.1. Esterification 2616 10.2. Ether Formation 2619 10.2.1. Etherification without Cyclization 2619 10.2.2. Etherification with Cyclization 2624 10.3. N-Alkylation 2625 10.4. Other Reactions 2627 11. Summary and Outlook 2628 12. Note Added in Proof 2628 13. Abbreviations Used in This Review 2629 14. Acknowledgments 2629 15. Supporting Information Available 2630 16. References 2630

Mitsunobu and Related Reactions: Advances and Applications

Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Tetrahedron report number 213

The SAMP-/RAMP-hydrazone methodology in asymmetric synthesis

2.1.3. Linker Bearing an Aromatic Ring 2053 2.2. Enynes and Diynes as Diene Component 2054 3. Photochemically Initiated DDA Reactions 2056 4. Mechanism of the DDA Reaction 2058 4.1. Mechanism of the Thermal DDA Reaction 2058 4.2. Mechanism of the PDDA reaction 2058 5. DDA Reactions Catalyzed by Bases 2058 6. Transition Metal-Catalyzed DDA reactions 2059 6.1. Rhodium and Platinum 2059 6.2. Palladium 2059 6.3. Gold 2061 7. Conclusions 2061 8. References 2062

The dehydro-Diels-Alder reaction.

Synthesis of isoindoloisoquinoline alkaloids. A revision of the structure of (±)-nuevamine

A comprehensive theoretical and experimental investigation of dehydro Diels-Alder reactions examining the evolution of the cyclic allene intermediates under conditions for intramolecular and ionic and radical intermolecular cycloaromatization processes is reported. Theoretical calculations showed that the most favored intramolecular path for cycloaromatization of 1,2,4-cyclohexatriene 4 and its benzoannulated derivative 14, strained cyclic allenes, consists of a pair of successive [1,2] H shifts rather than a [1,5] shift. Cycloaromatization of cyclic allenes may follow both inter- and intramolecular pathways, depending on the experimental conditions (use of protic or aprotic solvents). For synthetic purposes, the best procedure is to use a protic solvent to promote the ionic intermolecular route, the fastest and highest yielding. When the reaction is carried out in CCl4, intermolecular radical addition of chlorine to the cyclic allene competes with intramolecular aromatization paths. Theoretical calculations predict a low barrier for the reaction of cyclic allenes with carbon tetrachloride, and that the cyclic allenes act as nucleophiles in this reaction.

Cyclic allene intermediates in intramolecular dehydro Diels-Alder reactions: labeling and theoretical cycloaromatization studies.

Aryl radical cyclization in N-phenyl, N-benzyl, and N-phenethyl enaminone esters 1a-f was studied. N-Benzyl and N-phenethyl enaminones afforded 5-exo and 6-exo cyclization products, respectively, but radical cyclization did not occur in N-phenyl enaminones. The rate constants for the 5-exo and 6-exo cyclization processes in secondary enaminones were estimated as being on the order of 10(7) s(-1) at 353 K; since DNMR experiments showed the rate constant for rotation around the enaminone C3-N bond to be on the order of 10(4) s(-1) at this temperature, the initial enaminone configuration is maintained throughout the cyclization process. PM3 calculations suggested that the nonoccurrence of endo and 4-exo cyclizations is due to the corresponding transition structures involving significant distortion of the conjugated enaminone system.

Domingo Domínguez

Papers

Synthesis of isoindoloisoquinoline alkaloids. A revision of the structure of (±)-nuevamine

Cyclic allene intermediates in intramolecular dehydro Diels-Alder reactions: labeling and theoretical cycloaromatization studies.

A Study of Aryl Radical Cyclization in Enaminone Esters

An improved route to 4-demethoxydaunomycinone. A-Ring functionalization and resolution studies of tetracyclic precursors

Synthesis of the antitumoural agent batracylin and related isoindolo[1,2-b]quinazolin-12(10H)-ones