Enantioselective Allylation of Aldehydes Catalyzed by Diastereoisomeric Bis(tetrahydroisoquinoline) N,N′‐Dioxides

Abstract

AbstractEnantioselective allylation of aromatic and α,β‐unsaturated aldehydes with allyltrichlorosilane catalyzed by two diastereoisomeric (R,Rax,R)‐ and (R,Sax,R)‐bis‐1,1′‐[5,6,7,8‐tetrahydro‐3‐(tetrahydrofuran‐2‐yl)isoquinoline] N,N′‐dioxideswas studied. The course of the reaction was profoundly influenced by the chosen solvent. The (R,Sax,R) catalyst efficiently promoted the reaction in THF with enantioselectivity up to 96 %. On the other hand, the allylation of aromatic aldehydes in the presence of the (R,Rax,R) catalyst proceeded only in MeCN (up to 67 % ee), and the level of asymmetric induction was strongly influenced by the presence of electron‐donating and ‐accepting groups in the aldehyde. The allylation of α,β‐unsaturated aldehydes proceeded only in dichloromethane (enantioselectivity up to 68 %).