Lithium diethylphosphite

A recent paper [44] shows that the treatment of silyl thioketones 68 with lithium diethylphosphite proceeds via a thiophiUc attack followed by a thio-phosphate mercaptophosphonate (69 70) carbanionic rearrangement and the migration of the silyl group from the carbon to the sulfur atom leading to the S-silylated sulfanylphosphonate carbanion 71. The last step represents the first example of the thia-Brook rearrangement (Scheme 18). 

Add the lithium diethylphosphite solution to the imine 50 solution via a cannula and stir the resultant mixture at room temperature for 20 h. 

Later on, trimethylsilylcyanide and diethyl phosphorocyanidate (DEPC) were also found to activate the A -oxide in the above the Reissert-Henze reaction. In addition, lithium diethylphosphite was used as the nucleophile other than cyanide as shown in the transformation of N-methoxy pyridine 315 into the diethylphosphonate 316. ... 

It is possible, finally, to remove oxygen at position 3 altogether. This transformation starts by conversion of the hydroxyl at position 3 in estrone to its phosphite derivative, 25-1, by reaction with diethylphosphite chloride (Scheme 3.25). The resulting derivative is the treated with lithium in liquid ammonia. This reaction affords the deoxy derivative 25-3 the ketone at C17 is reduced to a p-hydroxyl group under the reaction conditions. 

The phosphonates (42) and (43) have been prepared by reaction of the respective 3 -ketonucleosides with the lithium salt of diethylphosphite, followed by a variation of the Barton deoxygenation procedure involving the radical catalysed deoxygenation of an intermediate mixed oxalate ester, followed by deprotection. The reaction with diethylphosphite is stereoselective, whilst the radical catalysed deoxygenation affords a p/a (42/43) ratio of about 2 1. 

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