One‐Pot Access to Sulfonyl 2‐Arylnaphthalenes via Wacker Oxidation of Sulfonyl o ‐Allylchalcones

2020 ◽  
Vol 362 (21) ◽  
pp. 4723-4735
Author(s):  
Nai‐Chen Hsueh ◽  
Min‐Chen Tsai ◽  
Meng‐Yang Chang
Keyword(s):  
One Pot ◽  
Wacker Oxidation

Total Synthesis of C–O Ring-Containing Natural Products

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Strong Support ◽  
Alder Reaction ◽  
Ring Closure ◽  
Columbia University ◽  
One Pot ◽  
Wacker Oxidation ◽  
National University

Scott A. Snyder at Columbia University demonstrated (J. Am. Chem. Soc. 2012, 134, 17714) that tetrahydrofuran 1 could be readily converted to oxocane 2 by treatment with the BDSB reagent developed in his laboratory. Reduction of 2 with DIBAL-H initiated a second ring closure by mesylate displacement to form the bicycle 3, which represented a formal total synthesis of laurefucin 4. Andrew L. Lawrence at the Australian National University found (Org. Lett. 2012, 14, 4537) that upon treatment with catalytic base, rengyolone 6, which was prepared in one pot from phenol 5, could be converted to the natural products incarviditone 7 and incarvilleatone 8. This demonstration provides strong support for the postulated biomimetic formation of these natural products. Shuanhu Gao at East China Normal University reported (Angew. Chem. Int. Ed. 2012, 51, 7786) the total synthesis of (+)-fusarisetin A 12 via biomimetic oxidation of equisetin 10 to produce the peroxy compound 11, followed by reduction. The bicyclic carbon skeleton of equisetin 10 was synthesized by intramolecular Diels-Alder reaction of trienyl aldehyde 9. The ellagitannin natural product (+)-davidiin 15 possesses a glucopyranose core with the unusual 1C4 (tetraaxial) conformation due to the presence of a biaryl bridge between two of the galloyl groups. Hidetoshi Yamada at Kwansei Gakuin University constructed (Angew. Chem. Int. Ed. 2012, 51, 8026) this bridge by oxidation with CuCl2 of 13, in which the three sterically demanding triisopropylsiloxy groups enforce the requisite tetraaxial conformation. John A. Porco, Jr. at Boston University applied (J. Am. Chem. Soc. 2012, 134, 13108) his asymmetric [3+2] photocycloaddition chemistry to the total synthesis of the aglain natural product (+)-ponapensin 20. Irradiation of hydroxyflavone 16 with methyl cinnamate 17 in the presence of diol 18 afforded the entire core framework 19 of ponapensin 20, which was accessed in just a few further synthetic transformations. Finally, Silas P. Cook at Indiana University reported (J. Am. Chem. Soc. 2012, 134,13577) a five-pot total synthesis of the antimalarial (+)-artemisinin 25. Cyclohexenone 21 was converted by simple operations to aldehyde 22. This aldehyde was then engaged in a [4+2] cycloaddition with the silyl ketene acetal 23 to produce, after an impressive Wacker oxidation of the disubstituted olefin, bicycle 24.

Alkene Reactions: The Xu/Loh Synthesis of Vitamin A1

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Phase Transfer ◽  
University Of Delaware ◽  
One Pot ◽  
Wacker Oxidation ◽  
Terminal Alkene ◽  
Peking University ◽  
Markovnikov Addition ◽  
The University ◽  
Convenient Preparation ◽  
Linear Product

Abdolreza Rezaeifard and Maasoumeh Jafarpour of the University of Birjand devised (J. Am. Chem. Soc. 2013, 135, 10036) an easily-scaled protocol for the Mo-catalyzed “on water” epoxidation of an alkene 1 to 2, using molecular O₂. Needing to epoxidize the sensitive alkene 3 to 5, Douglass F. Taber of the University of Delaware developed (Org. Synth. 2013, 90, 350) a convenient preparation of mmol quantities of the versa­tile oxidant dimethyldioxirane 4. Robert H. Grubbs of Caltech showed (Angew. Chem. Int. Ed. 2013, 52, 9751) that the Wacker oxidation of internal alkenes could proceed with high regioselectivity, as exemplified by the conversion of 6 to 7. David A. Nicewicz of the University of North Carolina demonstrated (J. Am. Chem. Soc. 2013, 135, 10334) the remarkable anti-Markovnikov addition of the acid 9 to the alkene 8, to give 10. Pieter C. A. Bruijnincx and Robertus J. M. Klein Gebbink of the University of Utrecht established (Chem. Eur. J. 2013, 19, 15012) a robust one-pot protocol for epoxidation, epoxide hydrolysis and periodate cleavage, for the net oxidative cleav­age of the alkene 11 to the aldehydes 12 and 13. Tomoki Ogoshi of Kanazawa University observed (Org. Lett. 2013, 15, 3742) that permanganate with a phase transfer catalyst could selectively oxidize the linear alkene 14 to 15 in the presence of branched alkenes. Davood Azarifar of Bu-Ali Sina University devised (Synlett 2013, 24, 1377) the reagent 17 as a useful alternative to ozone, as illustrated by the oxidation of 16 to 18. Ning Jiao of Peking University effected (J. Am. Chem. Soc. 2013, 135, 11692) the unsymmetrical cleavage of the alkene 19 to the nitrile aldehyde 20. Tiow-Gan Ong of the Academia Sinica added (Org. Lett. 2013, 15, 5358) 22 to the alkene 21 to give the linear product 23. This could be hydrolyzed to the acid, or reduced and hydrolyzed to the aldehyde. Joost N. H. Reek of the University of Amsterdam isomerized (ACS Catal. 2013, 3, 2939) the terminal alkene of 24 to the internal alkene, then hydroformylated that directly to give the α-methyl branched alde­hyde 25.

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