D. Knight
2019
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0
Influential Citations
7
Citations
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Journal
Advances in Heterocyclic Chemistry
Abstract
Abstract This review attempts to cover the use of 5-endo-dig cyclizations, “favored” as defined by Baldwin's rules, in the synthesis of heterocyclic and carbocyclic ring systems, ranging from furans, pyrroles, thiophenes, and their benzo-derivatives to cyclopentenes, indenes, and some more complex derivatives along with partly saturated examples. While some key contributions published prior to the turn of the millennium are included, the review consists predominantly of papers, which appeared after the year 2000. Despite that the original versions of Baldwin's rules were focused on nucleophile-driven processes, much of the considerable progress made in this area during this period has featured electrophile-driven cyclizations, often in a catalytic mode, the latter feature imbuing clear environmental advantages to many of these transformations. Hence, many examples have, as a key step, the attack of a nucleophilic center onto an activated alkyne, occasionally an allene, although these may be undetected intermediates in some cases. This defines the 5-endo-dig status of a particular transformation; because of the large volume of such contributions, this means that much closely related and useful methodology has had to be omitted. Brief sections on theoretical aspects and a summary of previously published reviews are also included.