Hoffmann-la Roche Inc.

Andreas Knierzinger

Arnold Trzeciak

Klaus Muller

Wilhelm Bannwarth

Daniel Obrecht

Alfred Grieder

Fernand Gerber

Michelangelo Scalone

There are described compounds of the formula ##STR1## Wherein the variables have been defined herein. The compounds are useful as research tools in the determination of biologically active peptides sequences and also potentially suitable as medicaments, some of them being useful in the prevention or control of the formation of blood platelet thrombi, and some compounds are useful as intermediates.

Tri- and tetracyclic compounds

Tri-and tetracyclic compounds

The invention relates to a process for the manufacture of vinylchromanes. This process is concerned with the manufacture of the compounds having the formula ##STR1## wherein R.sup.o is hydrogen or a cleavable protecting group, and comprises cyclizing a compound having the formula ##STR2## wherein R.sup.o is defined above and R.sup.1 is

Tocopherol synthesis: chromane cyclization and catalysis

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Birsfelden, Switzerland

Andreas Knierzinger