Hydrogallation of carbon-carbon multiple bonds proceeds in the presence of triethylborane as a radical initiator. Several functionalities do not interfere with this reaction. Resulting alkenyl- and alkylgallium species can be trapped by several electrophiles. Highly regioselective radical addition of an indium hydride reagent to alkynes is also achieved. Various functionalities are tolerant under the reaction conditions. The reaction proceeds with complete anti stereoselectivity. Alkenylindiums obtained via hydroindation can be employed for the following cross-coupling reaction with aryl halides in one pot.
Single electron transfer-induced cross-coupling reaction of alkenyl halides with aryl Grignard reagents
Alkenylhalides were found to undergo coupling with aryl Grignard reagents to give the corresponding styrene derivatives in a stereo-retained manner. The cross-couplingreaction is considered to proceed through a single electron transfer mechanism.