Tandem RCM of Dienynes for the Construction of Taxol-Type Carbocyclic Systems

Abstract

[reaction: see text] Tandem ring-closing metathesis of hydrindanone dienynes allows access to taxosteroids, a new class of compounds that combine the [5.3.1] carbocyclic system of taxanes with rings C and D of the steroid skeleton.

Transition‐Metal‐Mediated or ‐Catalyzed Syntheses of Steroids and Steroid‐Like Compounds

“…Interestingly, the relative stereochemistry at the 10-position also played an important role: (10R)-60 was successfully converted into the desired product 61 in 80 % yield (Scheme 23), whereas the corresponding reaction of its 10(S) diastereoisomer yielded a different product, due to steric effects. [58,59] Scheme 23. Granja's tandem alkene-alkyne-alkene metathesis.…”

Synthesis of 2‐Ene‐1,4‐diols by a New Cascade‐Opening of 1,3‐Diepoxides: Towards an Efficient Synthesis of Dihydroxytaxoid Derivatives

“…[3] Their framework (4) was prepared through a cascade ring-closing dienyne metathesis (RCDEYM) reaction from dienyne 5 (Scheme 1). [4] Herein, we report the transformation of derivatives 4 into taxanediols 6 by way of a new and general strategy.…”

Group‐Selective Ring‐Closing Enyne Metathesis

“…Granja et al also utilized a similar strategy to promote the formation of a disfavored eight-membered ring over that of a smaller, more favored five-membered ring (Scheme 6). [16] In their synthesis of a bridged bicyclic skeleton 21 by tandem enyne RCM, isopropyl substitution in 20 directed metathesis initiation to the least substituted alkene, which then led to ring closure to the eight-membered ring. Interestingly, this approach represents a rare example of the formation of bridged bicycles possessing a bridgehead double bond.…”