125828-06-0Relevant articles and documents
On the radical Brook rearrangement. Reactivity of α-silyl alcohols, α- silyl alcohol nitrite esters, and β-haloacylsilanes under radical-forming conditions
Paredes,Alonso
, p. 2292 - 2304 (2007/10/03)
Two alkoxyl radical generation methods, lead tetraacetate treatment of alcohols and photolysis of nitrites, were applied to α-silyl alcohols 21 and to the corresponding nitrites 25 with a view to forming α-silyl alkoxyl radicals 23 and studying their possible radical Brook rearrangement to α- silyloxy carbon radicals 24. LTA treatment of 21 led to their quick and efficient conversion into mixed acetyl-silyl acetals 33 under very mild conditions. Photolysis of α-alkylmonosubstituted α-silyl nitrites 25 to the corresponding aldehydes is considered to proceed through α-silyl alkoxyl radical intermediates 23. A concerted process is, however, proposed for the case of the benzyl nitrites analogues. On the basis of these results, it is postulated that resonance stabilization can have a major influence on the evolution of α-silyl alkoxyl radicals: should this stabilization be possible, they quickly evolve by α-silyl fragmentation; otherwise, they tend to undergo radical Brook rearrangement. It was also found that the radical Brook rearrangement of α-silyl cyclopropyloxyl radicals generated from β- bromoacylsilanes under standard tin-radical conditions is too slow to compete with β-fragmentation.
Synthesis of Acylsilanes from Amides and Esters, and the Selective Oxidation of α-Silyl Alcohols to Aldehydes
Fleming, Ian,Ghosh, Usha
, p. 257 - 262 (2007/10/02)
The acylsilanes 2 can easily be made directly from the dimethylamides 3 by treatment with phenyldimethylsilyllithium.They can also be made in two steps from the esters 4 using 2 equiv. of phenyldimethylsilyllithium followed by oxidation of the disilyl alcohols 5 with PDC.The disilyl alcohols 5 can be used as intermediates in the conversion of esters into aldehydes without recourse to hydride reagents, by monodesilylation, using a Brook rearrangement, followed by oxidation and selective removal of the silyl group, using chromium trioxide in DMSO.
