A synthesis of the quettamine skeleton 29 is described comprising ring closure
of the diastereomeric phenolic 1-(α-bromobenzyl)-tetrahydroisoquinolines
27a and 27b. In both cases only one diastereomer was obtained. NOE-experiments
confirm Shamma's assignments concerning the stereochemistry.
- Various attemps to cleave the dithiane derivative 5 of an α-amino
ketone in order to obtain the ketone 6 failed on account of the non-bonding
electron pair at the N-atom.

Wir beschreiben die Synthese des Quettamin-Gerüstes 29 durch Ringschluß
der diastereomeren 1-(α-Brombenzyl)-tetrahydroisochinoline 27a and 27b.
In beiden Fällen resultierte nur ein Diastereomer. NOE-Messungen bestätigen
Shamma's Aussagen zur Stereochemie. - Zahlreiche Versuche, das
Dithian-Derivat 5 eines α-Aminoketons zum Keton 6 zu spalten, schlugen
fehl wegen des nichtbindenden Elektronenpaars am Stickstoff.