Radical cyclizations and multicomponent radical cascades in solution were studied, which are initiated by intermolecular radical addition to C-C triple bond in alkynes as well as to related C?N triple bonds in nitriles and isonitriles. The reactions were arranged according to the atom that carries the unpaired electron in the attacking radical and cover main group IV-VI elements. The initial radical addition is highly regioselective and in reactions with substrates possessing several π systems, the alkyne moiety is usually attacked with high preference. This selectivity can be rationalized by the reversibility with which the initial radicaladdition occurs in many cases, in particular with Sn- and S centered radicals. Due to their high reactivity, vinyl radicals that are formed through radical attack at the alkyne moiety in enynes. Alkyl radicals resulting from radical addition to an alkene are far less reactive so that the competing dissociation and regeneration of the starting materials is often faster than the forward reaction steps.

Radical Cascades Initiated by Intermolecular Radical Addition to Alkynes and Related Triple Bond Systems

Carbo- and heterocycles are widely found in natural products, biologically active structures, medicinally relevant compounds, and in many other fine chemicals. The development of novel, general and efficient methods for their construction has therefore gained great interest in synthetic organic chemistry. Recently, radical chemistry has become a heavily investigated research field (a renaissance!). Along these lines, radical cascade cyclization of 1,n-enynes and diynes has emerged as a powerful strategy for the preparation of carbo- and heterocycles. In this review, we highlight recent advances in this rapidly growing area also focusing on reaction mechanisms.

Radical cascade cyclization of 1,n-enynes and diynes for the synthesis of carbocycles and heterocycles

http://su.diva-portal.org/smash/get/diva2:469764/FULLTEXT01.pdf

Hypervalent iodine reagents in the total synthesis of natural products.

Deep Sea Adriana Lorente,†,‡ Janire Lamariano-Merketegi,†,‡ Fernando Albericio,†,‡,§,# and Mercedes Álvarez*,†,‡,⊥ †Institute for Research in Biomedicine, Barcelona Science Park, University of Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain ‡CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Barcelona Science Park, Baldiri Reixac 10, 08028 Barcelona, Spain Department of Organic Chemistry, University of Barcelona, 08028 Barcelona, Spain School of Chemistry, University of KwaZulu-Natal, 4001-Durban, South Africa Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain

Tetrahydrofuran-containing macrolides: a fascinating gift from the deep sea.

A new metal-free oxidative radical [2+2+1] carbocyclization of benzene-linked 1,n-enynes with two C(sp(3))H bonds adjacent to the same heteroatom is described. This method achieves two C(sp(3))H oxidative functionalizations and an annulation, thus providing efficient and general access to a variety of fused five-membered carbocyclic hydrocarbons.

Metal-Free Radical [2+2+1] Carbocyclization of Benzene-Linked 1,n-Enynes: Dual C(sp3)-H Functionalization Adjacent to a Heteroatom

Macrolide magic: An enyne cross-metathesis reaction of an alkynyl boronate with an alkene derivative as well as a radical cyclization reaction of a homopropargylic β-alkoxyacrylate are the key transformations in the total synthesis of the cytotoxic macrolide (−)-amphidinolide K.

Hyung Kyoo Kwon

Papers

Total synthesis of (-)-amphidinolide K.

Radical cyclization of vinylic ethers: expedient synthesis of (+)-monocerin.

Total Synthesis of (-)-Amphidinolide K.