Researchers at the University of Buffalo in the US, led by Patricia Musacchio, have created a revolutionary photoredox system that redefines traditional chemistry by allowing the simultaneous introduction of two nucleophiles across a carbon\u2013carbon bond. Beginning with a basic benzylic carbon\u2013halogen (C\u2013X) framework, this novel method contradicts the conventional belief that such bonds can only experience single transformations. This technique has the ability to minimize the steps involved in chemical reactions and broaden the range of 1,2-disubstituted products.<\/p>\n
Normally, C\u2013X bonds are restricted to nucleophilic substitution or elimination reactions, permitting the incorporation of just one functional group at a time. Functionalizing two neighboring carbon atoms typically requires more intricate substrates like alkenes, dihalides, or multi-step methods. Musacchio’s group found that reacting a benzylic C\u2013X group with an iridium photocatalyst allows for the formation of a disubstituted product.<\/p>\n
At first, Musacchio proposed a typical SN<\/sub>2 substitution, followed by the activation of the benzylic C\u2013H bond by the photocatalyst. However, mechanistic investigations and density functional theory (DFT) analyses conducted by Jennifer Hirschi at Binghamton University disproved the notion of a sequential reaction or a halonium ion intermediate. Rather, the reaction encompasses an alkene radical cation. Ultraviolet (UV) light activation of the iridium photocatalyst produces a methoxy radical that extracts a benzylic hydrogen while concurrently cleaving the C\u2013X bond and generating a cation intermediate. One nucleophile attacks one position of the radical cation, followed by another nucleophile targeting the other carbon, yielding a range of disubstituted products from various benzylic halides and nucleophiles.<\/p>\n Hexafluoro isopropanol solvent is vital as it establishes a hydrogen bond network around the halogen leaving group, facilitating the fragmentation of the C\u2013X bond. The team also noted that in substrates with electron deficiency, the C\u2013X bond shifts between carbons, allowing for further transformations, such as palladium-catalyzed reactions.<\/p>\n Yi-feng Wang from the University of Science and Technology of China observes that Musacchio’s technique alters the synthetic utility of alkyl C\u2013X bonds, enhancing step efficiency and variety. The research team plans to broaden the substrate range and continue investigating the possibilities of employing two nucleophiles in 1,2 disubstitutions, viewing this method as a robust tool for creating molecular complexity.<\/p>\n","protected":false},"excerpt":{"rendered":" Researchers at the University of Buffalo in the US, led by Patricia Musacchio, have created a revolutionary photoredox system that redefines traditional chemistry by allowing the simultaneous introduction of two nucleophiles across a carbon\u2013carbon bond. Beginning with a basic benzylic carbon\u2013halogen (C\u2013X) framework, this novel method contradicts the conventional belief that such bonds can only […]<\/p>\n","protected":false},"author":2,"featured_media":374181,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"Default","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[174],"class_list":["post-374180","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-source-chemistryworld-com"],"_links":{"self":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/posts\/374180","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=374180"}],"version-history":[{"count":0,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/posts\/374180\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/media\/374181"}],"wp:attachment":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=374180"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=374180"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=374180"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}