Enantiomerically Pure Octahydronaphthalenone and Octahydroindenone: Elaboration of hte Substrate Overcame the Specificity of Yeast-Mediated Reduction

摘要

Substrate specificity on the reduction of bicyclic diketones with a yeast strain Torulaspora delbrueckii IFO10921 was investigated.Although this yeast efficiently reduces the isolated carbonyl group involved in the (S)-enantiomer of Wieland-Miescher ketone with high enantioselectivity 9E=126) the introduction of a substitutdent on the octahydronaphthalene skelecton as well as the structural change into an octahydroindene skeleton retarded the enxymatic reduction and the enantioselectivity fell to E=5-16 Further sturctural variation into a bicy-clo[3.30] skeleton led to an exclusive 1.4-conjugate reduction of the alpha,beta-unsaturated carbonyl group and the above results suggested the participation of plural oxidoreductive enzymes in the whole cell In turn among the 2,2-disubstituted cycloakanediones there were found good substrates to give the corresponding hydroxy ketone equivalents by yeast-mediated reduc-tion.The products were isolated as cyclic hemiacetals such as (1S,6S)-3-hydroxy-3.6-di-mthyl-2-oxabicyclo[4.3.0] nonan-7-one In addition the reduction worked well with use of an air-dried long-term jpreservable cell preparation The subse-quent chemical transformation warranted the stereo-chemistry and the stereochemical purity of the products which are related to octahycronaphthale-none and octahydroindenone systems that in turn are of considerable value as starting materials for terpenoid synthesis.