ChemInform Abstract: STUDY OF THE HYDROXYLATION OF N‐SUBSTITUTED 1,2,5,6‐TETRAHYDROPYRIDINES

Abstract

Die Oxidation der Tetrahydropyridine (I) mit Kaliumpermanganat in neutraler Lösung führt zu den cis‐Diolen (II).

Terminal Heck Vinylations of Chelating Vinyl Ethers

“…[12] In fact, performing the microwave-mediated Diels-Alder reaction with 3b under reductive conditions (by addition of 3 equivs. hydroquinone) did not lead to the aromatic compound 5b but rather to intermediate 4b.…”

“…[11] The presented knowledge suggested to us that chelation-controlled b-vinylation of vinyl ethers should provide a new gateway into valuable 1-alkoxy-1,3-butadienes. Since trans-alkoxydienes should be useful in the synthesis of cyclohexene derivatives by Diels-Alder reactions [12,13] and since classical preparative routes to this class of dienes appear rather toilsome, [14,15] more efficient procedures should be valuable.…”

N-Functionally substituted imines of polychlorinated (brominated) aldehydes and ketones

“…165 The methoxycarbonylimine 10a reacts with 1-alkoxydienes as a dienophile, the final reaction product, 1-methoxycarbonyl-2trichloromethyl-1,2-dihydropyridine 119, being formed in 84% yield upon elimination of an alcohol molecule with simultaneous migration of the double bond in the intermediate 118. 166 Chloral acylimines introduced in reactions with vinyl ethyl ether act as heterodienes, which leads to 2-alkyl-6-ethoxy-4trichloromethyl-5,6-dihydro-4H-1,3-oxazines 120a ± d. 167 Sulfonylimines are capable of forming [2+2]-cycloadducts. Thus the imine 2f reacts with trimethylsilyl ketene or ketene at room temperature to afford 1-propylsulfonyl-4-trichloromethylazetidin-2-ones 121a,b.…”