Organoborons are extremely important for synthetic organic chemistry; they can serve as advanced intermediates for a variety of transformations. Such a well-known transformation involves the loss of the boron moiety, creating alkyl radicals. Although these originally developed protocols for alkyl radical generation remain in active use today, in recent years their α-boryl carbon-centred radicals have been joined by a new array of radical generation strategies that offer a unique reactivity to forge a wider diversity of organoborons that often operate under mild and benign conditions. Herein, we will highlight the stability and reactivity of α-borylalkyl radicals and their remarkably recent advances in order to further utilise them for C-C and C-heteroatom bond formation. Their use for this purpose has been reported over the last decade in an attempt to guide the synthetic community. Various transition-metal and metal-free methods for their generation are presented, and more advanced photoredox approaches are discussed, mainly for the period of 2009-2019.
Bibliographical noteFunding Information:
A. M. is grateful to the Azrieli Foundation for the receipt of an Azrieli Fellowship. N. K. and R. R. R. are thankful to HUJI for a postdoctoral fellowship.
Dr Nivesh Kumar was born in New Delhi, India. He received his MSc degree from Delhi University, New Delhi in 2012 and his PhD degree from the Indian Institute of Science Education and Research (IISER)- Bhopal, India under the guidance of Prof. Alakesh Bisai in 2017. In 2018, he joined the group of Dr Ahmad Masarwa at The Hebrew University of Jerusalem, Israel.
© 2019 The Royal Society of Chemistry.