Silyloxy-Cope rearrangement

Fig. 2. Approach to the bicyclic core structure by silyloxy-Cope rearrangement. TES = triethylsilyl, Tf = triflate.

A general, asymmetric polyol synthesis has been developed by Schneider et al. [18] which takes advantage of the benefits of the silyloxy-Cope rearrangement of the chiral aldol product... 

Schneider, C. The silyloxy-Cope rearrangement of syn-aldol products evolution of a powerful synthetic strategy. Synlett 2001, 1079-1091. 

Addition of thiophenol to cyclopropylallene 12, a less common method for the preparation of cist tram mixtures of divinylcyclopropanes, is used in the synthesis of karahanaenone850, an odoriferous constituent of Japanese hop and cypress oil. Karahanaenone is also prepared via a silyloxy-Cope rearrangement of 15 in 54% overall yield (starting with isobutyraldehyde and a mixture of cis- and /rpyridinium chlorochromate oxidation to give 14)851-852,... 

For a related example which allows the introduction of functional groups via a combined phenylselenyl chloride functionalization/ silyloxy Cope rearrangement see ref 889. 

Silyloxy-Cope rearrangement of syn-aldol products (formation of tetrahydro-pyrans and piperidines used in syntheses of natural compounds) 01SL1079. 

TroponesReaction of vinyldiazomcthanes (1) with l-methoxy-l-(trimethyl-silyloxy)butadiene (2) catalyzed by rhodium(H) acetate or rhodium(ll) pivalate results in [3+4]cycloaddition via cyclopropanation/Cope rearrangement to form a cyclohcptadiene (3). Short exposure of 3 to citric acid followed by oxidation (DDQ) provides the... 

The well-known anionic Cope rearrangement of divinylcycloalkanols has been shown to be a useful method for the preparation of substituted cyclo-octenones [equation (18)]. The silyloxy version of this rearrangement is the variant... 

Bio, M.M. and Leighton, J.L. (1999) An approach to the synthesis of CP-263,114 a remarkably facile silyloxy-Cope rearrangement. Journal of the American Chemical Society, 121, 890-891. 

Kato, N., Takeshita, H., Tanaka, S., and Kataoka, H. (1989) Lactol-regulated silyloxy-Cope rearrangement and its application to the total synthesis of dictymal, an aldehyde possessing an iridoid dimeric structure./. Chem. Soc. Perkin Trans. L, 1833-1840. 

For large-ring systems of silyloxy-Cope substrates, however, the [1,3] shift is highly favored. In these rearrangements, the stereochemistry of the double bond is largely maintained, as demonstrated by the product distribution in the thermal rearrangement of (Z)- and ( )-l-trimethyl-siloxy-l-vinyl-3-cyclododecene (53)743. 

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