248250-08-0Relevant articles and documents
Intramolecular Diels-Alder reactions using α-methylene lactones as dienophile
Richter, Frank,Bauer, Matthias,Perez, Caroline,Maichle-Moessmer, Caecilia,Maier, Martin E.
, p. 2474 - 2480 (2007/10/03)
Several dienals were prepared and reacted in the presence of zinc metal with ethyl 2-bromomethylacrylate to provide in a Reformatsky-like reaction α-methylene lactones carrying a dienyl side chain. Thermolysis of these compounds (11, 21, 29, and 37) gave in an intramolecular Diels-Alder reaction the corresponding tricyclic cycloadducts (51, 52, 53, and 54). The cycloadditions took place with good diastereoselectivity and yields. The stereochemistry of the major isomer is in accordance with an endo transition state for cycloadducts 51, 52, and 54. In one instance (compound 58), the structure was supported by X-ray crystallography. In contrast to the other substrates, the nonatriene 29 cyclized to the exo product 53exo. The stereochemical situation could also be proven by NOESY NMR. However, the intramolecular Diels-Alder reaction did not work with furan as dienophile (compound 41) and substrate 50 featuring a densely functionalized tether connecting diene and α-methylene lactone.
Synthetic studies towards mniopetals (II). A short synthesis of Mniopetal E
Jauch
, p. 87 - 89 (2007/10/03)
A short total synthesis of Mniopetal E in thirteen steps is reported. Key steps are a new and highly diastereoselective lithium phenylselenide induced Baylis-Hillman reaction with Feringa's butenolide, an endo-selective intramolecular Diels-Alder reaction (IMDA) and a new variant of the Parikh-Doering oxidation.
A short synthesis of Mniopetal F?
Jauch, Johann
, p. 473 - 476 (2007/10/03)
The first total synthesis of Mniopetal F in fourteen steps is reported. Key steps are a new and highly diastereoselective lithium phenylselenide-induced Baylis-Hillman reaction with Feringa's butenolide, an endo-selective intramolecular Diels-Alder reaction (IMDA), inversion of a highly hindered secondary alcohol and a new variant of the Parikh-Doering oxidation.
A short total synthesis of kuehneromycin A
Jauch, Johann
, p. 2764 - 2765 (2007/10/03)
Only eleven steps were needed to synthesize kuehneromycin A (1) which inhibits reverse transcriptase (see picture). Key steps are a new variant of the Baylis-Hillman reaction, an endo-selective intramolecular Diels - Alder reaction, and a new protocol for
Synthetic studies towards mniopetals (I). A short synthesis of a key intermediate for the total synthesis of mniopetals
Jauch, Johann
, p. 1325 - 1327 (2007/10/03)
A short and efficient synthesis of a tricyclic core structure of mniopetals based on a new, highly diastereoselective PhSeLi induced Baylis- Hillman reaction and an endo-selective Intramolecular Diels-Alder reaction (IMDA) as key steps is presented.