Consecutive Ring-Expansion Reactions for the Iterative Assembly of Medium-Sized Rings and Macrocycles

TY - JOUR

T1 - Consecutive Ring-Expansion Reactions for the Iterative Assembly of Medium-Sized Rings and Macrocycles

AU - Stephens, Thomas C.

AU - Unsworth, William P.

N1 - © Georg Thieme Verlag. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2020/1/1

Y1 - 2020/1/1

N2 - Macrocycles and medium-sized rings have important applications in several scientific fields but can be challenging to make using traditional end-to-end cyclization reactions. Ring-expansion methods represent a useful alternative and offer numerous practical benefits. In this Account, we discuss the current state of the art of ring-expansion strategies that have been applied consecutively. Such methods have the power to expedite the design and synthesis of functionalized macro cycles via the selective, iterative insertion of smaller fragments into ring-enlarged products. 1 Introduction 2 Insertion Reactions 2.1 Transamidation/Transpeptidation 2.2 Transesterification 2.3 Transthioesterification 2.4 Aminyl Radical Cascade 2.5 Iterative Synthesis of Lactones 2.6 Successive Ring Expansion of β-Ketoesters and Lactams 3 Pericyclic Reactions 3.1 Sulfur-Mediated Rearrangements 3.2 Nitrogen-Mediated Rearrangements 4 Fragmentation Reactions 5 Conclusions and Future Outlook.

AB - Macrocycles and medium-sized rings have important applications in several scientific fields but can be challenging to make using traditional end-to-end cyclization reactions. Ring-expansion methods represent a useful alternative and offer numerous practical benefits. In this Account, we discuss the current state of the art of ring-expansion strategies that have been applied consecutively. Such methods have the power to expedite the design and synthesis of functionalized macro cycles via the selective, iterative insertion of smaller fragments into ring-enlarged products. 1 Introduction 2 Insertion Reactions 2.1 Transamidation/Transpeptidation 2.2 Transesterification 2.3 Transthioesterification 2.4 Aminyl Radical Cascade 2.5 Iterative Synthesis of Lactones 2.6 Successive Ring Expansion of β-Ketoesters and Lactams 3 Pericyclic Reactions 3.1 Sulfur-Mediated Rearrangements 3.2 Nitrogen-Mediated Rearrangements 4 Fragmentation Reactions 5 Conclusions and Future Outlook.

KW - iterative synthesis

KW - macro-cycles

KW - medium-sized rings

KW - rearrangements

KW - ring enlargement

KW - ring expansion

UR - http://www.scopus.com/inward/record.url?scp=85071189587&partnerID=8YFLogxK

U2 - 10.1055/s-0037-1611500

DO - 10.1055/s-0037-1611500

M3 - Article

AN - SCOPUS:85071189587

SN - 0936-5214

VL - 31

SP - 133

EP - 146

JO - Synlett

JF - Synlett

IS - 2

ER -