Abstracts of the 24th international isotope society (UK group) symposium: synthesis and applications of labelled compounds 2015.

The 24th annual symposium of the International Isotope Society's United Kingdom Group took place at the Møller Centre, Churchill College, Cambridge, UK on Friday 6th November 2015. The meeting was attended by 77 delegates from academia and industry, the life sciences, chemical, radiochemical and scientific instrument suppliers. Delegates were welcomed by Dr Ken Lawrie (GlaxoSmithKline, UK, chair of the IIS UK group).

Catalytic oxidative 1,2-shift in 1,1'-disubstituted olefins using arene(iodo)sulfonic acid as the precatalyst and oxone as the oxidant.

An efficient, catalytic hypervalent iodine-mediated oxidative 1,2-shift of 1,1'-disubstituted olefins is described. This methodology provides concise access to homobenzylic ketones with electron-donating substituents. In the case of cyclic systems, this transformation results in ring-expanded β-benzocycloalkanones, which are useful for further elaboration.

A general preparation of protected phosphoamino acids.

Fmoc-O-benzyl-l-phosphoserine is an important building block in the synthesis of Forigerimod, a phosphopeptide being investigated for Systemic Lupus Erythematosus (SLE). An efficient one-pot process was developed using inexpensive, readily available starting materials. This general procedure was used to prepare a variety of protected phosphoamino acids.

Asymmetric total synthesis of (-)-laulimalide: exploiting the asymmetric glycolate alkylation reaction.

A concise total synthesis of the potent antitumor macrolide (-)-laulimalide is described. The observation that homoallylic (or latent homoallylic) C-O bonds are present at C5, C9, C15, C19, and C23 led to the strategic decision to rely heavily on the asymmetric glycolate alkylation to construct both the C1-C14 fragment 3 and the C15-C27 subunit 4. A diastereoselective addition of a C1-C14 allylstannane to a C15-C27 alpha,beta-epoxyaldehyde served to join the two advanced fragments.

Asymmetric total synthesis of spongistatins 1 and 2.

The total synthesis of spongistatin 1 (1) and spongistatin 2 (2) has been achieved through an advanced-stage intermediate. The synthesis is highlighted by a highly convergent assembly of the four key fragments (the C1-C15 AB fragment 2, the C16-C28 CD fragment 3, the C29-C43 EF fragment 4, and the C44-C51 side chain 5) at a very advanced stage of the synthesis with minimal functional group interconversion. The CD fragment 3 functions as the central building block to which the other fragments are attached.

C-glycosides to fused polycyclic ethers. A formal synthesis of (+/-)-hemibrevetoxin B.

This paper describes a formal total synthesis of the marine ladder toxin hemibrevetoxin B from Danishefsky's dienes. This approach couples the generation of C-glycosides from cyclic enol ethers with metathesis or acid-mediated annulation reactions. The result is a highly efficient synthesis of the tetracyclic ring system of hemibrevetoxin B.

A highly efficient synthesis of the hemibrevetoxin B ring system.

[reaction: see text] This Letter describes the synthesis of the hemibrevetoxin B tetracyclic ring system in 14 linear transformations from the Danishefsky-Kitahara diene.