Eight-membered ring templates for stereoselective radical cyclizations
TL;DR: The ratio of cyclization to reduction of the cyclodec-6-enylmethyl radical depends critically on the alkene geometry as mentioned in this paper, which is a structural feature of the taxane diterpenes.
About: This article is published in Tetrahedron Letters.The article was published on 1988-01-01. It has received 16 citations till now. The article focuses on the topics: Radical cyclization.
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01 Jan 1998
TL;DR: The application of organotins in organic synthesis has become a major field of organom et al. lic chemistry during the last decade as mentioned in this paper and the incredible development and sophistication of known basic chemistry now allows organotin to be essential tools for the organic chemist, very often used in the preparation of natural products.
Abstract: The application of organotins in organic synthesis has become a major field of organom et al. lic chemistry during the last decade. The incredible development and sophistication of known basic chemistry now allows organotins to be essential tools for the organic chemist, very often used in the preparation of natural products.
6 citations
TL;DR: In this paper, various functionalized derivatives of trans-2,6-dimethylcyclooct-5-enol have been prepared and found to be recalcitrant to free radical or ionic six-ring cyclization with formation of a new carbon-carbon bond syn to the original hydroxy group at the pro-quaternary site.
Abstract: Various functionalized derivatives of trans-2,6-dimethylcyclooct-5-enol have been prepared and found to be recalcitrant to free radical or ionic six-ring cyclization with formation of a new carbon–carbon bond syn to the original hydroxy group at the pro-quaternary site. However, intramolecular syn delivery was achieved with complete regiocontrol by epoxidation/ring opening of the MOM ether, oxidation to the α,β-unsaturated ketone 35a, RhI-catalysed hydrosilylation to give 36, and exposure of this silyl enol ether to stannic chloride in the presence of ‘proton sponge’. The pivotal ring closure leads in good yield to 32, thereby solving the problem posed by untoward kinetic barriers to ring closure that are present under alternative conditions.
4 citations
28 Feb 2018
2 citations
TL;DR: Taxol (paclitaxel) is the best-selling natural-source anticancer drug ever produced and one of the most common prescriptions in the treatment of breast, lung, and ovarian cancers, saving countless lives around the world as discussed by the authors .
Abstract: Taxol (paclitaxel), the most well-known taxane diterpenoid, is the best-selling natural-source anticancer drug ever produced and one of the most common prescriptions in the treatment of breast, lung, and ovarian cancers, saving countless lives around the world. Structurally, Taxol possesses a highly oxygenated [6-8-6-4] core bearing 11 stereocenters, seven of which are contiguous chiral centers. Moreover, the extremely strained bicyclo[5.3.1] undecane ring system with a bridgehead double bond is a unique structural feature. All these features make Taxol a highly challenging synthetic target. Tremendous synthetic efforts from more than 60 research groups around the world have already culminated in ten total syntheses and three formal syntheses, as well as more than 60 synthetic model studies of Taxol. This review is intended to provide a long-overdue appraisal of the great achievements in the total syntheses of Taxol reported in the last few decades. In doing so, we summarize the development of synthesis toward Taxol from 1994 to 2022, including the evolution of synthetic strategy for accessing this complex molecular scaffold and key lessons learned from such endeavors. Finally, we briefly discuss the future of the research in this area.
1 citations
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613 citations
TL;DR: In this paper, the conformational properties of medium and large-ring organic molecules have profound consequences on the stereochemical course of their chemical reactions, and the diastereomeric composition of the products was determined.
282 citations
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