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Shionane-Baccharane Group

Methyl trisnorshionanoate (126) has been synthesized from friedelan-19a-ol (127) via the ring-contracted intermediate (128) and the trisnor-ketone (129). Irradiation of (129) in methanol afforded the desired ester (126). An investigation of the effect of solvent on the backbone rearrangement of 3/8,4/3-epoxyshionane (130) by boron trifluoride etherate has shown that nucleophilic solvents tend to interrupt the rearrangement at an early stage (see Vol. 6, p. 130). [Pg.168]

The baccharane derivative (131) is formed by Lewis acid-catalysed rearrangement of both the a- and /3-epoxides (132) and (133) of the A -isomer of betulin diacetate. The rearranged product has been synthesized by an independent (131) route. The stereochemistry of the /S-epoxide (133) has been confirmed by X-ray analysis. [Pg.168]

Yokoyama, T. Hirao, T. Tsuyuki, Y. Moriyama, T. Murae, and T. Takahashi, Tetrahedron Letters, 1977, 273. [Pg.168]

See other pages where Shionane-Baccharane Group is mentioned: [Pg.168]    [Pg.153]    [Pg.296]    [Pg.141]    [Pg.361]    [Pg.168]    [Pg.153]    [Pg.296]    [Pg.141]    [Pg.361]    [Pg.666]   


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Shionane

Shionanes

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