Borane Catalyzed Hydrogenation And Hydrosilylation

In recent years,frustrated Lewis pairs has developed rapidly,which has become one of the most efficient synthetic methods in metal-free catalytic system.However,it is difficult to synthesize chiral frustrated Lewis pairs catalyst.A limited substrate scope,enantioselectivities,and the type of catalyst have necessitated the development of new catalytic system.In this paper,we expanded the range of substrates and types of catalysts.1.A metal-free hydrogenation of 2-quinolinecarboxylates was successfully realized for the first time by using 5 mol % of B(C6F5)3 as catalyst to furnish a wide range of cyclic ?-amino ester derivatives in 57-99% yields.An attempt for the asymmetric hydrogenation with the frustrated Lewis pair of Cy3 P and chiral boron Lewis acid generated in situ from chiral diene gave the desired product with 14% ee.2.A metal-free hydrosilylation of chromones and flavones was successfully realized for the first time with the use of in situ generated borane catalyst by hydroboration of pentafluorostyrene with HB(C6F5)2.A variety of chromanones and flavanones were obtained in 60–99% yields.It is noteworthy that only 0.1 mol % catalyst loading can ensure a high reactivity.3.We have basically completed the asymmetric hydrosilation of acetophenone with the frustrated Lewis pair of tBu3 P and chiral boron Lewis acid generated in situ from chiral diene or chiral olefin.