Allenes and Cumulenes

Crabbe and his co-workers have described how the organocopper intermediate 

Miyaura, M. Itoh, and A. Suzuki, Bull. Chem. Soc. Japan, 1977, 50, 2199. 

After last year s preliminary report on the synthesis of pentatetraene by a retro-Diels-Alder reaction involving flash thermolysis of (131), Ripoll has now published the full details and has also shown that the similar decomposition of ll-vinylidene-9,10-ethano-9,10-dihydroanthracene (132) at 750°C-10mm-Hg pressure gives an 85% yield of butatriene (133). To complement these developments, a timely publication has appeared on the theoretical basis and the instrumentation necessary for flash thermolyses, suitable for such experiments on a preparative scale. 

---

Chemistry of Ketenes, Allenes and Related Compounds", S. Patai (ed.), John Wiley and Sons, Chichester, New York, Brisbane, Toronto, (1980). lOe. H. Hopf, "The Preparation of Allenes and Cumulenes", Chapter 20 in "The Chemistry of Ketenes, Allenes and Related Compounds", S. Patai (ed.), John Wiley and Sons, Chichester, New York, Brisbane, Toronto, (1980). 

It will be convenient to consider under one heading all those unsaturated systems which do not fall under any of the sections previously discussed. There are four categories which are included in this catch-all heading. They are pyridones, quinones, multiple substitution at nonequivalent sites, allenes and cumulenes, and conjugated dienes and polyenes. 

In recent years The Chemistry of Functional Groups series has included three volumes on composite functional groups in which a C=C double bond was attached to another group. The chemistry of enones (edited by S. Patai and Z. Rappoport) appeared in 1989 The chemistry of enols (edited by Z. Rappoport) appeared in 1990 and The chemistry of enamines (edited by Z. Rappoport) appeared in 1994. We believe that the time has arrived for a book dealing with the combination of C=C double bonds, namely dienes and polyenes. The two double bonds can be conjugated, and conjugated dienes have a chemistry of their own, but even non-conjugated dienes show certain reactions that involve both double bonds. Allenes and cumulenes, which represent a different combination of the double bonds were treated in The chemistry ofketenes, allenes and related compounds, edited by S. Patai in 1980. 

Synthesis of Acetylenes, Allenes and Cumulenes A Laboratory Manual by L. Brandsma and H.D. Verkruijsse... 

Brandsma, L. Verkruijsse, H. D. "Synthesis of Acetylenes, Allenes, and Cumulenes A Laboratory Manual" Elsevier New York, 1981 p. 55. 

Brandsma L (1981) Synthesis of acetylenes allenes and cumulenes. Elsevier, Amsterdam... 

Brandzma, L., Verkruijsse, H. D. Synthesis of Acetylenes, Allens and Cumulenes. Elsevier, Amsterdam 1981... 

Hopf, H. The preparation of allenes and cumulenes. in The Chemistry ofKetenes, Allenes and Related Compounds (ed. Patai, S.), 2, 779-901 (John Wiley Sons, New York, 1980). 

---