Trimethylsilyl triflate Subject

Pyrone (361) reacted with /wra-benzoquinone when subjected to laser irradiation in an oxygen atmosphere to give a mixture of products which included the trioxane (42) (18%) <88JOC4986>. Reaction of compound (371) with singlet oxygen, followed by treatment of the reaction mixture with trimethylsilyl triflate, gave the trioxane (388) (6%) <90CC726>. 

Optically active 2-substituted- 1,3-propanediol derivatives were prepared as shown in equation 45. The bis-trimethylsilylated 1,3-diols were condensed with /-menthone in the presence of trimethylsilyl triflate to give the corresponding diastereomeric ketals, which were separated and subjected to further transformations. For example, the cleavage was carried out via a Mukaiyama reaction to generate the a-alkoxy ketone, which could be protected and then cleaved to the optically active, unsymmetrical, monoprotected 1,3-diol52. 

When subjected to the action of trimethylsilyl triflate and acetic anhydride, careful control of the reaction conditions leads to cyclodextrin 11 by selective replacement of the ben2yl groups from the primary rim by acetates (Scheme 9.5) [19]. The position 3 can also be selectively deprotected by the action of triethylsilane and iodine at low temperature, giving access to cyclodextrin 12 bearing a functionahzation pattern similar to cyclodextrin 9a [20]. These reactions illustrate another approach toward the selective modification of cyclodextrins selective removal of already installed groups, which is the counterpart to the selective installation of functional groups. 

Similarly, (tropone)iron complexes can also be subjected to this reaction (Scheme 4-25). Treatment of an (T -tropone)iron complex with trimethylsilyl triflate provides an Tj -dienyliumiron complex salt with an additional silyl enol ether moiety. 

The imine 188, derived from 3-(trimethylsilyl)-2-propynal and (S)-a-methyl-benzylamine, was treated at — 40 °C with the born enolate 187 prepared from S-phenyl butanethioate, 9-borabicyclo[3.3.1]nonyl triflate and DIPEA. After workup, a mixture of the anti p-amino acid 189 and the syn adducts 190 was formed in a 5.2 1 ratio. This mixture was then subjected to cyclization using tert-butylmagnesium chloride in diethylether to give the trans P-lactam 191 in... 

Kobayashi and co-workers introduced 2-(trimethylsilyl)phenyl triflate as an aryne precursor subject to benzyne formation without the need of a strong base. Fluoride-induced desilylation and rapid elimination of the sulfonate provide efficient access to benzyne in acetonitrile at room temperature (eq 1). Other solvents such as THF, acetone, dichloromethane, DME, and toluene may be used, but such conditions may require heating for benzyne formation and frequently afford diminished yields. Preparation of the benzyne intermediate is even possible in protic media, albeit with decreased efficiency and limited applicability in subsequent reaction steps. ... 

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