Synthesis of the spiroketal core of integramycin

• Evgeny. V. Prusov

Beilstein J. Org. Chem. 2013, 9, 2446–2450, doi:10.3762/bjoc.9.282

• treatment with sodium periodate furnished pure 13. The primary hydroxy group was selectively converted to alkyl iodide by using Ph3P/I2/imidazole conditions [10]. Then the protected iodide 14 was subjected to Myers alkylation [11] reaction with an excess of enolate to install the last required stereocenter

• epoxidation and Myers alkylation. Although the presented route achieves approximately the same overall yield of target compound as that of Floreancig [2] (11.2 vs 11.5%, respectively), it features utilization of easily scalable transformation and upon further optimization of the spiroketalization step would

• , Microbial drugs). Retrosynthetic analysis of integramycin. Synthesis of the aromatic subunit. Sharpless epoxidation/Myers alkylation approach to the C16–C22 carboxylic acid fragment. Coupling of the fragments and spiroketalization. Supporting Information Supporting Information File 527: Experimental

Exploration of an epoxidation–ring-opening strategy for the synthesis of lyconadin A and discovery of an unexpected Payne rearrangement

• Brad M. Loertscher,
• Yu Zhang and
• Steven L. Castle

Beilstein J. Org. Chem. 2013, 9, 1179–1184, doi:10.3762/bjoc.9.132

• stereoselective sequence involving a Myers alkylation and a Shi epoxidation. Ring-opening of this epoxide with a vinylcopper complex afforded alcohol 26 instead of the expected product 27. An unusual Lewis acid promoted Payne rearrangement of an α-trityloxy epoxide is proposed to account for this outcome

• . Keywords: Lewis acid; lyconadin A; Myers alkylation; Payne rearrangement; Shi epoxidation; Introduction Lyconadin A (1, Figure 1) was isolated from the club moss Lycopodium complanatum in 2001 by Kobayashi and co-workers [1]. Subsequent to this discovery, lyconadins B–F were isolated and characterized [2

• would ultimately be formed by a Myers alkylation [23] of (+)-pseudoephedrine derived amide 7 with allylic iodide 8. The initial epoxidation substrate of type 6 that we targeted possessed benzyl and TBDPS ethers as the protecting groups. First, allylic iodide 8 was synthesized by iodination of the

Efficient syntheses of 25,26-dihydrodictyostatin and 25,26-dihydro-6-epi-dictyostatin, two potent new microtubule-stabilizing agents

• María Jiménez,
• Wei Zhu,
• Andreas Vogt,
• Billy W. Day and
• Dennis P. Curran

Beilstein J. Org. Chem. 2011, 7, 1372–1378, doi:10.3762/bjoc.7.161

• Scheme 2, which is a streamlined version of prior routes in the 16-desmethyl series [14]. (However, some material 7 was also made by an extension of a prior middle fragment route, as described in Supporting Information File 1, Scheme S1). Myers alkylation [17] of commercially available pseudoephedrine