Die Epoxysulfoncyclofragmentierung,eine neue Ringerweiterungsmethode. Synthese von rac.-Muskon

A new ring expansion method using the cyclofragmentation of epoxysulfones; a synthesis of rac. muscone. Starting from the readily available cyclododecanone 1 the hydroxy sulfone 5 has been prepared using standard procedures. Subsequent dehydration followed by an acidic equilibration resulted in a mixture of two endocyclic olefines, from which the olefin 7 showing the (E)-configuration could be isolated by fractional crystallization. Oxidation of 7 produced the epoxy sulfones 8 and 9 . The epoxy sulfone 8 was cyclized to the hydroxy sulfone 10 without any detectable amount of the corresponding epimer 11 . Fragmentation of the intermediate 10 using KOTB produced pure (E)-4-muscenone 12 . The epoxy sulfone 9 was cyclized to a mixture of the two epimeric hydroxy sulfones 14 and 15 . Fragmentation of the two crystalline hydroxy sulfones 14 or 15 with KOTB produced a mixture of 12 and 16 . The ‘one-pot’ preparation of (E)-4-muscenone 12 starting from 8 could also be accomplished. The configurational assignements within this serie are based upon the data of an X-ray analysis of the hydroxy sulfone 10 .     

Die thermolyse von n-alkoxycarbonyl-phosphinimiden. eine neue phosgenfreie isocyanat-synthese

The thermolysis of N-alkoxycarbonyl-phosphinimides X₃PN-CO-OR (X = Ar, n-Bu) and N-alkoxy-carbonyl-phosphorimidates (X = EtO, PhO) gives alkylisocyanates and alkylisocyanurates at 120°–280° in yields of 20–62 resp. 15–26%. The identification of the by-products of this reaction is described.