알킬 아자이드로부터 생성된 N-미치환 이민 유도체의 거울상 선택적 알릴화 반응을 통한 광학 활성을 가진 호모알릴아민의 선택적 합성

Abstract

Homoallylamine is known as one of the most important compounds in organic synthesis. By the versatile transformation of double bonds, chiral homoallylamines have been used as intermediates in synthesis of natural products and pharmaceuticals. Developing new methods for preparation of chiral homoallylamines has drawn the attention due to the importance in organic chemistry. One of the efficient ways to achieve homoallylamines is nucleophilic allylation reaction of imine moieties. Imine has unsaturated C=N bond which has similar properties with carbonyl compounds. In most studies, more stable N-protected imines have been employed. Free imines, however, are difficult to prepare directly owing to their instability. From synthetic viewpoint, N-protected imines require removal of the substituent to access the amine product. In this regard, the use of N-unsubstituted imines would be ideal in that the elimination step is not necessary. Accordingly, the development of practical methods for the synthesis of free imines is highly desirable. Recently, some useful methods were reported for the preparation of N-unsubstituted imine. Though these methodologies provided quite satisfactory results in enantioselective reactions, they only worked with non-enolizable imines due to their reaction conditions. Very lately, a new method using a dimeric Ru catalyst for the in situ generation of N-unsubstituted imines from alkyl azides was developed. The allylation of an N-unsubstituted imine with ((-)-Ipc2B(allyl)) provided the corresponding homoallylamine with a good yield. Due to the neutral and mild condition, both enolizable and non-enolizable imines could be achieved with great chemoselectivity. Because it doesn’t include necessity of removal of protection group, this method can be very efficient ways to synthesize highly functionalized chiral homoallylamines.