Iridium hydrides hydroalkoxylation

Intramolecular hydroalkoxylation of internal alkynes containing proximate oxygen nucleophiles was catalyzed by iridium hydride complex [48] (Scheme 29). The cyclization of 2-alkynylbenzyl alcohols follows highly selective 6-endo-dig regiochemistry for both alkyl and aryl substituents on the multiple bond. Cyclization of substrates having two OH groups gave spiroacetal derivatives. When... [Pg.249]

Li X, Chianese AR, Vogel T, Crabtree RH (2005) Intramolecular alkyne hydroalkoxylation and hydroamination catalyzed by iridium hydrides. Org Lett 7 5437-5440... [Pg.285]

Iridium(ni) hydrides, such as (98), proved to be air-stable active catalysts for intramolecular hydroalkoxylation and hydroamination of internal alkynes with proximate nucleophiles (e.g. 96). The cyclization follows the 6-endo-dig pathway with high preference (when regioselectivity is an issue).125... [Pg.310]

An iridium(m) hydride catalyzed intramolecular alkyne hydroalkoxylation can be used to construct isochromans 545 bearing a C(3)-spiroacetal moiety (Equation 226) <2005OL5437>. Novel isochromans bearing an array of C(3)-spiroacetal moieties are accessible via the hydroboration of alkynediols with disiamylborane followed by treatment of the resulting alkenylboron compounds with alkaline hydrogen peroxide <1998CL81>. [Pg.531]

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