Diiodomethane-Samarium

Addition a to a cyano group Benzyltriethylammonium chloride, 239 Nickel, 197 Addition a to halogen Diiodomethane-Samarium, 113 Fluoromethyl phenyl sulfone, 135 Tris(dimethylamino)sulfonium difluo-rotrimethylsilicate, 336 Addition a to oxygen... 

Cyclopropanols and their derivatives Diiodomethane-Samarium, 113 Trimethylstannylmethyllithium, 331 Cyclopropyl aldehydes, ketones, esters, etc. 

Samarium Compounds t-Butoxydiiodosamarium, 272 Diiodomethane-Samarium, 113 Diiodomethane-Samarium iodide, 113 Samarium, 113... 

Reduction of A,(V-di bcnzy lam i noalkyl chloromethyl ketones 133, followed by spontaneous intramolecular ring closure of the resulting 7-chloroamines 134, afforded azetidinium salts 135, which were subsequently deprotected toward chiral 3-hydroxyazetidines 136 and 137 (Scheme 29) <1997JOC1815>. In a similar approach, ct-amino aldehydes 138 were converted into 3-hydroxyazetidinium salts 139 upon treatment with diiodomethane and samarium iodide, followed by stabilization using AgBF4. Ar-Dealkylation with Pd afforded enantiopure azetidines 140 (Scheme 30) <2000TL1231>. 

In recent years, exposing the preparation of the reagent from samarium metal and an oxidant to different stimuli has led to significant improvements in reaction time. Concellon utilized the sonication of samarium metal and iodoform at room temperature to give a solution of Sml2 in THF in approximately 5 min (Scheme 2.3).5 This approach was also used by Flowers to synthesise other Sm(II) species.6 It was also reported that using different oxidants, such as 1,2-diiodoethane, diiodomethane and iodine, works just as well with this technique.5... 

When a-halo ketones are treated with diiodomethane and samarium at 0 °C, cyclopropanols can be obtained in reasonable yields. Curiously, under the same conditions 1,2-dibenzoylethane also leads to cyclopropanol products (equations 34 and 35). Several pathways for conversion of a-halo ketones to the observed cyclopropanols can be envisioned. It has been proposed that the mechanism of this reaction involves reduction of the a-halo ketone by Sm (or Smh) to a samarium enolate. Cyclopropanation of this enolate with a samarium-based carbenoid subsequently provides the observed product. 

Certain vinylstannanes will undergo cyclopropanation with diiodomethane and samarium amalgam.69 71 Epoxidation of the double bond can be carried out with meta-chloroperoxybenzoic acid,71,72 and the kinetic resolution of a 3-stannylallyl alcohol has been achieved under Sharpless conditions (equation 8-38)73... 

The zinc metal in the Simmons-Smith reaction was replaced by samarium for the cyclopropanation of allylic alcohols with chloroiodomethane. High yields of cyclopropanes, often with high diastereoselectivities, were obtained using samarium amalgam/diiodomethane. Cyclo-hex-2-enol (115a) gave exclusively s y -bicyclo[4.1.0]heptan-2-ol (116a), no traces of the anti-... 

Samarium(II) iodide and diiodomethane efficiently cyclopropanated lithium enolates 119 under very mild conditions, providing a convenient route to cyclopropanols 120. 

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