Enantioselective Reaction of Diketene to Aldehydes Promoted by Chiral Titanium Complexes

光学活性5-羟基-3-氧酯可以转化为6-取代的4-羟基内酯，这是紧实蛋白和甲维苷的常见结构成分，被称为3-羟基-3-甲基戊二酰辅酶A （HMG-CoA）还原酶的抑制剂。最近，我们成功地利用新型手性席夫基烷氧钛配合物促进二烯酮与醛的对映选择性反应，高效地制备了具有光学活性的5-羟基-3-氧酯。这一新方法为光学活性5-羟基-3-氧酯的合成提供了一种有效的方法，其对映体过量（ee）可达92%。

Optically Active 5-hydroxy-3-oxoesters can be converted into 6-substituted 4-hydroxy lactones which are common structural components of compactin and mevinolin known as inhibitors of 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase. W e recently succeeded in the highly efficient preparation of optically active 5-hydroxy-3-oxoesters by enantioselective reaction of diketene with aldehydes promoted by novel chiral Schiff basetitanium alkoxide complexes. This new procedure provides an efficient method for the synthesis of optically active 5-hydroxy-3-oxoesters in up to 92% enantiomeric excess (ee).