Progress in allene chemistry.

During the last three decades the chemistry of allenes has fascinated scientists worldwide. Thus, its beauty has been recognized in a diversity of allenic natural products, many of them showing interesting or promising therapeutic activities. In fact, around 150 natural products containing an allenic or cumulenic structure have been identified. In the meantime, the reactivity of allenes has been studied showing novel interesting patterns where chemo-, regioand diastereoselectivity issues have been addressed. Cycloaddition, cross-coupling and cycloisomerization reactions, among others, have been studied affording a huge collection of structures. As long as allenes are showing us their reactivity, many strategies deal with the synthesis of allenic derivatives. The main goal of this themed issue is to provide a multidisciplinary view of the chameleonic allenemoiety – from synthesis, structure, and reactivity, to properties. It will also highlight the key centre-to-axis chirality transfer used in many processes. The objective of this issue is to bring together contributions from a significant group of high quality chemists in order to integrate concepts in allene chemistry and to act as a reference for scientists in the area. The issue combines tutorial reviews with review articles to illustrate the versatility of the cumulated diene system of allenes. The ease of synthesis and the exceptional reactivity of alkoxyallenes has led to their use in a large number of highly diverse applications. Tius (DOI: 10.1039/ C3CS60333D) describes their use in a Grupo de Lactamas y Heterociclos Bioactivos, Departamento de Quı́mica Orgánica, Unidad Asociada al CSIC, Facultad de Quı́mica, Universidad Complutense de Madrid, 28040-Madrid, Spain. E-mail: [email protected]; Fax: +34 91-3944103 b Instituto de Quı́mica Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006-Madrid, Spain. E-mail: [email protected]; Fax: +34 91-5644853