Recent advances in the synthesis of naturally occurring pyrrolidines, pyrrolizidines and indolizidine alkaloids using proline as a unique chiral synthon Chinmay Bhat and Santosh G. Tilve * The present article describes the synthesis of a wide spectrum of natural products of the class pyrrolidines, pyrrolizidines and indolizidines using proline as a viable synthetic precursor. The review emphasizes the versatility of the basic unit of proline as a useful chiral synthon confined for the synthesis of only natural products of the above mentioned families. The vast coverage of the synthesis of these natural products is presented for a period from 1990 onwards. The synthesis of all ranges of alkaloids from simple to complex molecules is presented under the groups of alkaloids. 1. Introduction Over the last few decades, asymmetric synthesis of natural products has gained major importance from an industrial and academic relevance. 1 Asymmetric synthesis mainly involves; carrying out the reaction with the integrity of the chiral centre viz. “chiral pool” strategy, introducing new chiral centres by chiral induction methods, use of chiral auxiliaries and orga- nocatalysis. It is always difficult to carry out selective transformation of the molecules to generate new chiral centres. Although the use of organocatalysis is soaring nowadays, selectivity towards the substrates, efficacy of the systems and cost of organocatalysts make this cumbersome from an economic point of view. On the other hand, the “chiral pool” approach, being an effectual paradigm, plays a very prominent role from synthetic relevance 2 as the starting materials are easily carved from readily available materials like amino acids, carbohydrates, terpenes and organic acids. A vast number of natural products are derived from different amino acids 3 due to the availability of the functional groups suitable for various transformations to effect the required modications and constitute new appendages. As a consequence, several amino Chinmay Bhat received a BSc from Dr A. V. Baliga College Kumta, Karnataka. He joined the department of chemistry, Goa University, Goa to study for a Master of Science in Chem- istry. He obtained a MSc in 2008 in organic specialization. He qualied CSIR-NET-JRF in December 2007. He continued further studies in the same department under the supervi- sion of Prof. S. G. Tilve to pursue his doctoral research. Presently he is working on asymmetric synthesis of pyrrolidine and piperidine alkaloids using chiral pool strategy. His research interests include the synthesis of bioactive molecules, organocatalysis and heterocyclic chemistry. Prof. Santosh G. Tilve received his BSc and MSc from Bombay University. He obtained a PhD in 1989 from Pune University under the supervision of Prof. R. S. Mali. Aer working in the chemical industry for six months, he started his academic career as a lecturer at Goa University. He was promoted to associate professor in 1999 and to full professor in 2007. He worked as a visiting fellow with Prof. I. Blair at the Pennsylvania University (USA) in 2000-2002. Presently, he is the Head of Chemistry Department, Goa Univer- sity. His current research interests include asymmetric synthesis, heterocycles, green chemistry, domino reactions and nano composites as catalysts. Department of Chemistry, Goa University, Taleigao-Plateau, Goa 403 206, India. E-mail: stilve@unigoa.ac.in; santoshtilve@yahoo.com; Fax: +91-0832-2452889; Tel: +91-0832-6519317; +91-0832-2452886 Cite this: RSC Adv. , 2014, 4, 5405 Received 6th August 2013 Accepted 21st October 2013 DOI: 10.1039/c3ra44193h www.rsc.org/advances This journal is © The Royal Society of Chemistry 2014 RSC Adv. , 2014, 4, 5405–5452 | 5405 RSC Advances REVIEW Published on 22 October 2013. Downloaded by Indian Institute of Science Education and Research Mohali on 30/01/2014 09:21:03. View Article Online View Journal | View Issue