An efficient methodology for the indirect anti-Markovnikov hydration of unsymmetrically substituted terminal and internal alkynes is based on TiCl 4 -catalyzed hydroamination reactions. Its application to ortho-alkynylhaloarenes, followed by a copper-catalyzed O-arylation, provides flexible access to substituted benzo[b]furans.

A catalytic enantioselective synthesis of the antimelanoma marine natural product (-)-palmerolide A was accomplished using a longest sequence of 21 steps and without resorting to stoichiometric chiral auxiliaries or the chiral pool. The right half was constructed with a new variant of the Claisen-Ireland rearrangement exploiting an alkenylboronate as a masked hydroxyl. The left half featured the first application of a diol.SnCl(4)-catalyzed enantioselective crotylboration in the context of a complex target. This distinct strategy could pave the way to the design of simplified analogues of palmerolide.

[reaction: see text] An intermolecular hydroamination reaction of norbornene is presented that uses catalytic amounts of user-friendly TiCl(4) and tolerates a variety of functional groups. In addition, a secondary amine is converted using this methodology.

Two distinct economical catalysts for intramolecular hydroaminations of electronically unactivated alkenes with basic amines are described, which are based on (a) group 4 metal halides under basic reaction conditions or (b) Brønsted-acid organocatalysts.

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A one-pot indole synthesis consisting of a highly regioselective TiCl(4)-catalyzed hydroamination and a 5-endo Heck cyclization starting from 2-chloroaniline is described, using an in-situ generated, sterically hindered imidazol-2-ylidene palladium complex.

The Lewis acid TiCl4 allows the intermolecular hydroamination of vinylarenes (see scheme). Some of the hydroamination products undergo rearrangements to give ortho‐alkylated compounds. The catalyst tolerates a range of functional groups (R′=CF3, Cl, CN, F, Br) and provides the products in good yields. This method was also applied to the synthesis of a tetrahydroisoquinoline derivative.

Titanium-catalyzed intermolecular hydroaminations of (E/Z)-chloroenynes enabled an efficient pyrrole synthesis, which set the stage for the development of a user-friendly one-pot reaction for the regioselective preparation of fully substituted pyrroles from easily accessible alpha-haloalkynols.