Rhodium-Catalyzed Hydroallylation of Activated Alkenes

Abstract

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Tuning of α-Silyl Carbocation Reactivity into Enone Transposition: Application to the Synthesis of Peribysin D, E-Volkendousin, and E-Guggulsterone

“…Compound 27 after desilylation using TBAF and KOH furnished diene 28 in 80% yield. Finally, diene 28 upon reaction with molecular oxygen in the presence of Rose Bengal in EtOH resulted in cyclic peroxide, which was reduced in situ with NaBH 4 to give peribysin D. 21 All of the spectral data, including 1 H and 13 C NMR data, were in agreement with the literature report. 17 It was clear from our previous work that the structure of peribysin D may need to be stereochemically revised (see ref 4).…”

“…In addition, fluoride- and alkoxide-based reagents were unsuccessful in the desilylation reaction (Table , conditions 5–7) . The use of HMPA along with TBAF as reported by Muraoka et al gave an ∼20% yield of the desired product . Capperucci et al have reported a condition under which TBAF and KOH were used in combination for the proto-desilylation of the triphenyl silyl group .…”

“…12 The use of HMPA along with TBAF as reported by Muraoka et al gave an ∼20% yield of the desired product. 13 Capperucci et al have reported a condition under which TBAF and KOH were used in combination for the proto-desilylation of the triphenyl silyl group. 14 Under the same condition, we observed successful removal of the phenyl dimethyl silyl group, which furnished product 3d in 64% yield when refluxed in THF for 16 h. The reaction time was significantly decreased when the reaction was carried out in a microwave at 85 °C with an excellent yield of 98% (Table 1, entry 10).…”