Di-r-butylsilylene

The di-r-butylsilylene group has been used to connect a diene and a dienophile to control the intramolecular Diels-Alder reaction. ... 

As opposed to the thermally induced reactions, the photolysis of 2 takes place by simultaneous cleavage of two Si-Si bonds to give di-r-butylsilylene 4 and tetra-f-butyldisilene 5, both of which can be trapped by numerous addition or cycloaddition reactions [13]. 

The first total synthesis of concanamycin F by Toshima et al. also utilized di-r-butylsilyl bis(trifluoromethanesulfonate) for protection of 1,3-diols. The key aldol reaction between 11 and 12 was best achieved using PhBCl2 and i-Pr2NEt in CH2CI2 at —78 °C to provide the desired aldol 13 as the sole isomer in 84% yield. The selective deprotection of di-r-butylsilylene was then achieved using HF-pyridine, which resulted in concomitant... 

Under these optimized conditions, di-tert-butylsilylene could be transferred to a range of acyclic and cyclic olefins (Schemes 7.9 and 7.10).11,74 The method was not sensitive to the steric nature of the R substituent nearly quantitative silylene transfer to olefins bearing ra-butyl, isopropyl, or tert-butyl groups was observed. Vinylsilanes were also tolerated as substrates. Olefins containing silyl ether, benzyl ether, and pivolate substituents were all effective traps of di-tm-butylsilylene. 

In a separate communication, Kita and coworkers also reported an enantiodivergent synthesis of an ABODE ring analog of the antitumor antibiotic fredericamycin A via an intramolecular [4 + 2] cycloaddition. Late-stage oxidations were performed on the di-f-butylsilylene for protection of phenolic hydroxyl groups. Syntheses of both (R)- and (5)-enantiomers were reported (eq 18). ... 

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