Asymmetric Baylis-Hillman Reaction: An Enchanting Expedition

Krishna, Palakodety Radha; Sachwani, Rachna; Reddy, P. N.

doi:10.1055/s-0028-1087338

Cited by 59 publications

(7 citation statements)

References 15 publications

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“…Scheme illustrates construction of the B-ring and introduction of the five stereogenic centers (C1, C6, C7, C8, and C10) starting from enantiopure ( R )-glycerol acetonide ( 11 ). Swern oxidation of 11 using (COCl) 2 , DMSO, and i -Pr 2 NEt afforded unstable aldehyde 12 , which was directly subjected to a Morita–Baylis–Hillman reaction . The crude 12 was coupled with ethyl acrylate in the presence of DABCO at 10 °C without solvent, leading to a 2.8:1 diastereomeric mixture of alcohols 13 and C1- epi -13 .…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of Euonymine and Euonyminol Octaacetate

et al. 2021

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Euonymine (1) and euonyminol octaacetate (2) share the core structure of euonyminol (3), the most hydroxylated member of the dihydro-β-agarofuran family. In 2, eight of the nine hydroxy groups of 3 are acetylated, and 1 has six acetyl groups and a 14-membered bislactone comprising a pyridine dicarboxylic acid with two methyl groups. The different acylation patterns provide distinct biological activities: 1 and 2 display anti-HIV and Pglycoprotein inhibitory effects, respectively. The 11 contiguous stereocenters and 9 oxygen functionalities of the ABC-ring system of 1 and 2 represent a formidable challenge, which is further heightened by the macrocyclic structure of 1. Here we disclose an efficient synthetic strategy for enantioselective total synthesis of 1 and 2. Starting from (R)-glycerol acetonide, we constructed the Bring by an Et 3 N-accelerated Diels−Alder reaction, the C-ring by intramolecular iodoetherification, and the A-ring by ring-closing olefin metathesis. The 10 stereocenters were installed through a series of substrate-controlled stereoselective C−C and C−O bond formations by exploiting the three-dimensional structures of judiciously designed substrates. These newly developed reaction sequences led to protected euonyminol 5, which served as a common intermediate for assembling 1 and 2. Global deprotection of 5 and subsequent acetylation produced 2. Alternatively, the discriminative protective groups of 5 allowed for site-selective bisesterification to generate bislactone. Combining [3 + 2]-cycloaddition and reductive desulfurization introduced the last remaining stereocenters of the two methyl groups on the macrocycle. Finally, deprotection and acetylation gave rise to fully synthetic 1 for the first time.

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Section: Resultsmentioning

confidence: 99%

Total Synthesis of Euonymine and Euonyminol Octaacetate

et al. 2021

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“…[4] Over the last few years, we have been involved in expanding the synthetic utility of the Baylis-Hillman reaction. [5] The diastereoselective version of this reaction results in products wherein the newly created chiral center is predominantly anti to the existing one.…”

Section: Introductionmentioning

confidence: 99%

First Stereoselective Total Synthesis of Isoaspinonene through a Baylis–Hillman/Olefin Cross‐Metathesis Protocol

2011

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“…The chemistry of indoline-2,3-dione (isatin) − functionalization at the 1,3,4,5,6-positions leads to attractive applications among major classifications of chemical, biological, and medicinal fields of science. Functionalization of these positions is well established in the literature, such as Morita–Baylis–Hillman addition reaction − (MBH adduct formation at C-3 position), substitution reactions ( N -alkylation, aromatic electrophilic substitution), oxidation, and reduction. To conduct one particular reaction in the core structure of the isatin molecule, some of the positions have to be protected using protection–deprotection chemistry.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Substituted Isatins from the MBH Adduct of 1,5,6-Trisubstituted Isatins Using (2,4-Dinitrophenyl)hydrazine and K-10 Clay Explored as Protection–Deprotection Chemistry

et al. 2019

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An interesting synthetic transformation of protection–deprotection chemistry in an isatin molecule is achieved. Morita–Baylis–Hillman (MBH) adduct formation used as protection of the C-3 position in the isatin molecule is reported. C–C bond cleavage in the MBH adduct of isatin with the help of phenylhydrazine and C=N bond cleavage in the phenylhydrazone derivative of isatin with the help of K10 clay are studied systematically and reported as deprotection.

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Asymmetric Baylis-Hillman Reaction: An Enchanting Expedition

Cited by 59 publications

References 15 publications

Total Synthesis of Euonymine and Euonyminol Octaacetate

Total Synthesis of Euonymine and Euonyminol Octaacetate

First Stereoselective Total Synthesis of Isoaspinonene through a Baylis–Hillman/Olefin Cross‐Metathesis Protocol

Synthesis of Substituted Isatins from the MBH Adduct of 1,5,6-Trisubstituted Isatins Using (2,4-Dinitrophenyl)hydrazine and K-10 Clay Explored as Protection–Deprotection Chemistry

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