Silylcarbinols, Brook rearrangement

The retro-1,2-Brook rearrangement was used in a stereocontrolled synthesis of bis-silylated enals and enones (e.g., 152). Deprotonation of propargyl silyl ether 150 led to cr-silylcarbinol 151 via the West rearrangement. The product was best isolated upon cold quench with trifluoroacetic acid. The bis C-silylated propargyl alcohol 151 was the substrate for a stereoselective Lewis acid-catalyzed conversion to enal 152. ... 

The a-silylcarbinol rearrangement, discussed in Section IV,B, was discovered by Brook and his students as early as 1958, but was not recognized as an anionic rearrangement until later (5). 

Long before the silyl Wittig rearrangement was discovered, the base-catalyzed rearrangement of a-silylcarbinols to alkoxysilanes was known. This reaction, carefully studied by Brook and his students (4-6) takes place in exactly the opposite direction to the silyl Wittig reaction. In the... 

Brook had set the basis for developing the reaction that came to bear his name, but clearly many mechanistic details remained to be elucidated. In addition, Brook did not anticipate the potential utility of the rearrangement, in fact concluding the 1959 paper with what turned out to be wholly unwarranted self-deprecation It is doubtful whether the rearrangement reported here will have much synthetic application since in general silyl ethers are much more readily prepared than are the corresponding a-silylcarbinols. ... 

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