Total Synthesis of taxol. 2. Construction of A and C ring intermediates and initial attempts to construct the ABC ring system
摘要:
A method for the formation of Taxol's ABC ring system has been developed. General methods for the synthesis of versatile synthons for Taxol's A ring (8) and C ring (55) are presented. A model study using a simplified C ring synthon (17) confirmed the viability of the sequential Shapiro-McMurry strategy for formation of Taxol's B ring. Careful exploration of the chemistry of various A-B ring conjugates allowed the development of a successful method for formation of the B ring in a more functionalized system.
Diastereoselective triple radical cyclization of a bromomethyldimethylsilyl allyl ether
作者:Andrew S. Kende、Michel Journet、Richard G. Ball、Nancy N. Tsou
DOI:10.1016/0040-4039(96)01383-4
日期:1996.8
A convergent strategy to construct the B-ring in an AC → ABC cyclization to the taxane framework was tested. The bicyclic bromomethyldimethylsilylether 2 was efficiently synthesized by a sequence proceeding through the alkylation of the C-ring malonate 4 by the hindered A-ring bromide 3. The desired tandem 5-exo-trig/8-exo-dig cyclization of 2 to diol 1 was not observed. An alternative pathway was