Regio- and Stereoselective Aminopentadienylation of Carbonyl Compounds

A simple
and robust protocol is detailed for the preparation of
enantioenriched α-substituted (1,4-pentadien-3-yl)­amine derivatives.
The methodology involves the addition of an in situ formed pentadienyl
indium reagent to chiral tert-butylsulfinimines,
previously formed in the same pot. The addition takes place with excellent
γ-regio- and diastereoselectivity for a wide range of carbonyl
compounds, including α-unsubstituted aldehydes and methyl alkyl
ketones. The catalytic hydrogenation of the sulfinamines obtained
provides a convenient access to chiral α-substituted (3-pentyl)­amines.
The hydroboration–oxidation of the α-(1,4-pentadien-3-yl)­amine
derivatives, followed by a cyclization under Mitsunobu conditions,
takes place with an excellent diastereoselectivity governed by the
chiral sulfinyl group.

本文详细报道了一种简便且稳健的合成方案，用于制备对映富集的α-取代(1,4-戊二烯-3-基)胺((1,4-pentadien-3-yl)amine)衍生物。该方法采用原位生成的戊二烯基铟试剂(pentadienyl indium reagent)与同一反应釜中预先制备的手性叔丁基亚磺酰亚胺(chiral tert-butylsulfinimines)发生加成反应。对于包括α-未取代醛、甲基烷基酮在内的多种羰基化合物底物，该加成反应均可实现优异的γ区域选择性与非对映选择性。对所得亚磺酰胺进行催化加氢，可便捷获得手性α-取代(3-戊基)胺。对α-(1,4-戊二烯-3-基)胺衍生物进行硼氢化-氧化反应后，再经Mitsunobu条件(Mitsunobu conditions)下的环化反应，在手性亚磺酰基(chiral sulfinyl group)的调控下可获得优异的非对映选择性。