Inside and outside N-bridge cavity systems: evidence for syn- and anti-atropisomers in scaffolds containing two N-benzoyl 7-azanorbornane units

Alkene and aziridine reagents containing N-benzoyl 7-azanorbornane components have been prepared and used to construct [n] polynorbornanes in a block building protocol. The presence of syn- and anti-atropisomers involving the restricted rotation of the N-COPh bridge was established by 1H NMR spectroscopy in an NNN-[3]polynorbornane 4 (outside bridges) whereas the anti-conformer dominated in a cavity NCOCOCN-[7]isopolynorbornane 8 (inside bridges, X-ray confirmation) prepared by a dual 1,3-dipolar addition of an acute-angled norbornene 6 with a hexacyclic bis-epoxide 7

A concise, regio and stereoselective route to fluorinated protoberberines via tandem addition-cyclisation reactions of phthalide anions with 3,4-dihydroisoquinolines

A series of fluorinated protoberberines have been prepared by condensing fluorinated phthalide anions with 6,7-dimethoxydihydroisoquinoline. The spectroscopy and stereochemistry of the products are discussed and the stereochemical outcome of the reactions rationalised. (C) 1998 Elsevier Science Ltd. All rights reserved