Phenyltelluroacrylonitriles and phenylselenoacrylonitriles as precursors of (Z)-α-phenylseleno-α,β-unsaturated aldehydes, β-amino-α-phenylselenonitriles and Diels–Alder adducts
摘要:
Reaction of cyanomethylphosphonate with aryl selenenyl (or tellurenyl) halides and aldehydes, under basic conditions, provides alpha -phenylseleno or alpha -phenyltelluro acrylonitriles in good yields. Reaction of the alpha -phenylseleno acrylonitriles with dienes furnishes the corresponding adducts while reaction with amines furnishes alpha -phenylseleno-beta -amino nitriles. Selective reduction of the cyano group with DIBAL-H results in the alpha -phenylseleno-alpha,beta -unsaturated aldehydes. (C) 2001 Elsevier Science Ltd. AU rights reserved.
The synthesis of regio- and stereoselective arylsubstitutedα,β-unsaturated aldehydes and ketones from activated allenes was achieved. This mild and non-metallic oxidation is exclusively driven by benign ambient air and triggered by visible light. The same starting materials under ideal anaerobic conditions led to the 2,3-diphenylselenation adduct with no trace of oxygenated products, demonstrating
some cases. In THF, [2,3]-sigmatropic rearrangement of allylic selenoxides, selenimides, and dihalo-selenuranes occurred, yielding allenyl alcohols 12–15, allenyl carbamates 16c–19c, and 1-haloalkyl allenes 20c–22c, respectively.