Diastereoselective Synthesis of Tetrahydrofurans via Mead Reductive Cyclization of Keto-β-Lactones Derived from the Tandem Mukaiyama Aldol Lactonization (TMAL) Process
نویسندگان
چکیده
منابع مشابه
A tandem non-aldol aldol Mukaiyama aldol reaction.
[reaction: see text] A new one-pot tandem aldol process is described in which a secondary epoxy silyl ether is converted into the 1,5-bis-silyloxy-3-alkanone in good yield. Thus, treatment of the epoxy silyl ether 8 with TBSOTf and base affords the silyl enol ether 9 via non-aldol aldol rearrangement and addition of benzaldehyde and TBSOTf gives the ketone 10 with 4:1 syn selectivity. The diast...
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An organocatalyzed Michael-cyclization cascade approach of readily available α,β-unsaturated aldehydes and pyrazoleamides has been developed to get highly substituted δ-lactones in excellent enantioselectivities (up to 97%) and diastereoselectivities. The δ-lactones so obtained could easily be transformed into benzazepine derivatives with excellent enantio- and diastereoselectivities. Furthermo...
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A new and imaginative technique for the synthesis of substituted pyranoquinoline via Algar Flyn Oyamanda oxidation cyclization approach has been achieved by hydrogen peroxide and sodium hydroxide catalyzed of quinoline chalcone with intramolecular cyclization to formed pyranoquinoline. In this reaction, two new C-C bonds were formed in a one step with high atom economy. The possible reaction pa...
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Palladium-catalyzed oxidative cyclization of alkenols provides a convenient entry into cyclic ethers but typically proceeds with little or no diastereoselectivity for cyclization of trisubstituted olefins to form tetrahydrofurans due to the similar energies of competing 5-membered transition-state conformations. Herein, a new variant of this reaction has been developed in which a PdCl2/1,4-benz...
متن کاملA concise synthesis of tubuphenylalanine and epi-tubuphenylalanine via a diastereoselective Mukaiyama aldol reaction of silyl ketene acetal.
We have developed a straightforward and auxiliary-free synthetic route towards tBu-tubuphenylalanine (tBu-Tup) and tBu-epi-tubuphenylalanine (tBu-epi-Tup), which are the key components of tubulysins and their analogs. A Lewis acid-mediated diastereoselective Mukaiyama aldol reaction using silyl ketene acetal and N-Boc-L-phenylalaninal provided γ-amino-β-hydroxyl-α-methyl esters, which were deox...
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ژورنال
عنوان ژورنال: The Journal of Organic Chemistry
سال: 2007
ISSN: 0022-3263,1520-6904
DOI: 10.1021/jo7014246