Synthesis of Optically Active Thiadecalins and Thiahydrindans by a Proline-Catalyzed Intramolecular Michael Reaction

The trans-thiadecalindione 1 and the trans-and cis-thiahydrindandiones 2 and 3 were prepared from the corresponding α-thio enones 4 and 5 by a proline-catalyzed intramolecular Michael process. The optically pure enantiomers of 1 were obtained by fractional crystallization, allowing the assignment of an enantiomeric excess of 19-28% for the Michael reaction depending on reaction conditions. Additionally, thiadecalindione 1 was reduced by actively fermenting bakers' yeast to provide exclusively the product 7 resulting from reduction of the thiopyran ring carbonyl group.