New α,β-unsaturated valerolactams showing potential as Michael acceptors were synthesized fromheterocyclicimines as starting materials. The synthetic procedure is based on an acid chloride addition in the first step, followed by a modified Hosomi-Sakurai reaction, and a final ring-closing metathesis using a ruthenium catalyst. heterocycles - imines - unsaturated lactams - Michael acceptor - ring-closing
Homo- and heterogeneous organocatalysis: enantioselective Mannich addition of ketones to endocyclic carbon–nitrogen double bonds
作者:Knut Schulz、Lars Ratjen、Jürgen Martens
DOI:10.1016/j.tet.2010.10.079
日期:2011.1
The proline-catalyzed Mannich addition of ketones to chalkogenazines is reported. Yields and enantioselectivities of the corresponding products were good to excellent, using different types of organocatalysts. Furthermore the immobilization of hydroxyproline into a readily synthesized polystyrene-copolymer was accomplished. The catalytic performance of this heterogeneous catalyst was successfully demonstrated