Approach to the synthesis of pyrrolizidine and indolizidine derivatives via nitro alkyl addition to enals. New adventures in benzylic activation cyclopropanation of benzylchlorides

Ashe, Maria (2016) Approach to the synthesis of pyrrolizidine and indolizidine derivatives via nitro alkyl addition to enals. New adventures in benzylic activation cyclopropanation of benzylchlorides. University of Southampton, Chemistry, Masters Thesis, 97pp.

Record type: Thesis (Masters)

Abstract

Organocatalysis is a rapidly developing and important part of organic chemistry allowing the development of new, environmentally friendly methodologies. In this thesis we report a diastereoselective and enantioselective cyclopropanation reaction catalysed by secondary amines.

In the first project (Chapter 2) we present an attempt at a total synthesis of pyrrolizidine and indolizidine derivatives utilising an organocatalytic approach in a key step. The proposed route could give access to diazabicyclic compounds in five or six steps starting from commercially available materials.

In the second project (Chapter 3) we present a developed methodology for organocatalytic cyclopropanation. We used benzyl chlorides decorated with electron withdrawing groups (EWG) in combination with a weak base to activate benzylic position and a range of ?,?-unsaturated aldehydes to achieve the desired products with good and excellent yields, good diastereoselectivity and excellent enantioselectivity.

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