Samarium diiodide synthesis

For some excellent recent reviews of the utility of samarium diiodide in organic synthesis, see (a) Molander, G. A. Chem. Rev. 1992, 92, 29 (b) Soder-quist, J. A. Aldrichimica Acta 1991, 24, 15. 

The blue samarium diiodide solutions are stable indefinitely in the absence of water and oxygen, and Sml and Ybl2 solutions have been employed as reducing agents in organic synthesis. 

The asymmetric synthesis of unsymmetrical vicinal diamines by samarium diiodide induced reductive coupling of nitrones derived from aUphatic aldehydes with optically pure N-tert-butanesulfinyl aromatic imines has been recently reported [41]. For example, the reaction between nitrone 55 and... 

Crombie and Rainbow reported synthesis of terminal dienes of high. E-selectivity via samarium diiodide mediated scission of 2-vinyl-3-chlorotetrahydrofuran (equation 175) or the corresponding pyran derivatives296. Interestingly, both cis- and frans-2-substituted 3-chlorotetrahydrofurans give the same diene, indicating the involvement of identical intermediates formed by electron transfer from samarium diiodide. 

More recently, Doris et al. have described the reductive ring-opening of a-keto epoxides [16]. In this manner, p-hydroxy ketones can be obtained in high yields. The synthesis of enantiomerically pure compounds can easily be realized. The titanocene] 111) reagents are distinctly superior to samarium diiodide, which is also known to induce this transformation. 

Novel synthetic procedures for indolizidine alkaloids were developed via a samarium diiodide-promoted carbon-nitrogen bond cleavage as a key step. Application of the procedure led to the total synthesis of (+)-(8R, 8aR)-perhydro-8-indolizidinol <2006H193>. 

Han XY, Xu F, Luo YQ, Shen Q (2005) An efficient one-pot synthesis of dihydropyrimidi-nones by a samarium diiodide catalyzed Biginelli reaction under solvent-free conditions. Eur J Org Chem 1500-1503... 

A. Chenede, E. Perrin, E. D. Rekai, and P. Sinay, Synthesis of C-disaccharides by a samarium diiodide induced intramolecular coupling reaction of tethered sugars, Synlett p. 420 (1994). 

Procter DJ, Flowers RAII, Skrydstrup T (2009) Organic synthesis using samarium diiodide. RSC, Cambridge... 

Organic Synthesis Using Samarium Diiodide A Practical Guide By David J. Procter, Robert A. Flowers, II and Troels Skrydstrup David J. Procter, Robert A. Flowers, II, Troels Skrydstrup 2010 Published by the Royal Society of Chemistry, www.rsc.org... 

Organic Synthesis Using Samarium Diiodide A Practical Guide... 

There exists also a synthesis of cyclopentadecanone (VII/81) and ( )-mus-cone, based on a three-carbon annulation of cyclic ketones followed by the regioselective radical cleavage of the zero bridge of the so formed bicyclic system [44], The synthesis of cyclopentadecanone is summarized in Scheme VII/16. The cyclization of VII/78 to the bicyclic alcohol VII/79 proceeds best (94 % yield) with samarium diiodide in the presence of hexamethylphosphoric acid triamide and tetrahydrofuran [45], The oxidative cleavage of VII/79 to the ring expanded product VII/80, was performed by treatment with mercury(II)-oxide and iodine in benzene, followed by irradiation with a 100 Watt high pressure mercury arc. Tributyltinhydride made the de-iodination possible. 

J. L. Chiara, J. Marco-Contelles, N. Khira, P. Gallego, C. Destabel, and M. Bemabe, Intramolecular reductive coupling of carbonyl-tethered oxime ethers promoted by samarium diiodide A powerful method for the stereoselective synthesis of aminocyclopentitols, J. Org. Chem., 60 (1995) 6010-6011. 

---