Taxane diterpenes 2: Synthesis of the 7-deoxy ABC taxane skeleton, and reactions of the A-ring

Recent Advances in the Chemistry of Aminocyclitols

“…These are versatile synthetic intermediates amenable to further transformations into a wide variety of functional groups 49. The intramolecular version of this reaction has been successfully applied to the elaboration of nitro‐substituted cycloalkanes in the context of the total synthesis of some natural products 50,51. In particular, this reaction has been used in the synthesis of nitrocyclohexanol adducts starting from D ‐glucose52 and also in the synthesis of inositols through subsequent removal of the nitro group under radical conditions ( n ‐Bu 3 SnH/AIBN) 53.…”

Recent synthetic developments in the nitro to carbonyl conversion (Nef reaction)

“…70 This strategy has also been used for the synthesis of the A-ring of taxane diterpene 145 starting from nitroalkene 144 (Scheme 41). 71,72 Organometallic addition to nitroalkenes allows the When dimethyldioxirane is used as an oxidant for this purpose, however, the intermediate anion is transformed into the corresponding phenol 161. 77,78 The oxidation is likely to proceed through an oxaziridine 159 that is hydrolysed to the cyclohexadienone 160 that readily tautomerise to the more stable phenol 161 (Scheme 45).…”

Application of [5+2] cycloaddition toward the functionalized bicyclo[4.3.1]decane ring system: synthetic study of phomoidride B (CP-263,114)Preliminary communication: N. Ohmori, Chem. Commun., 2001, 1552.

“…This was next treated with NaCN and subsequent elimination of HBr gave a β-cyanized compound 34 in 96% yield (2 steps). 20 With nitrile 34 in hand, cyclopropanation was examined and a sulfonium ylide turned out to be most effective for this transformation of electron-deficient enone 34, providing the desired cyclopropane compound 35 (61%) as a single isomer. This cyclopropanation occurred by way of the less hindered exo-face of the oxabicycle.…”