Samarium/Methylene iodide

Cyclohexadienones, not unexpectedly, can been employed to obtain alkylphenolic systems. Thus a solution of the p-quinone methide depicted when slowly introduced in tetrahydrofuran solution over 2 hours into samarium(ll) iodide at 35°C followed by work-up with sodium bicarbonate solution gave a 67% yield of (E)-2-(3,5-dimethyl-4-hydroxyphenyl)cyclopentanol. The Smij was obtained by treating samarium during 1 hour with methylene diiodide in tetrahydrofuran at 0"C and reacting for a further hour (ref.9). 

A radical-mediated two-step synthesis of spiroketals has recently been reported the strategy (an example is shown in Scheme 8) involves an intramolecular radical cyclization of a ketal precursor (14), which could be easily prepared from 2-methylene-3,4-epoxyoxolanes (13). As alternative to tin-hydride mediated cyclization of alkynyl halides, samarium(II) iodide has been used to generate the alkyl radical which adds intramolecularly to the triple bond. ... 

New syntheses of enamino-ketones by the ring-opening of isoxazoles with samarium di-iodide and with pentacarbonyliron, by the reaction of 2-alkyl-thiomethyl-3-alkylthioacrylophenones with amines, and by the intramolecular photoarylation of A -[2-(haloaryl)ethyl]-(3-enaminones, of enamino-diketones by the reaction of (3-chlorosulphonic acid chlorides with amines and by amino-methylenation of cyclic (3-dicarbonyl compounds, and of enamino-esters by aminomethylenation of esters and lactones and by the reaction of nitriles with magnesium enolates have been reported. 

---