β-Carbon Elimination from Cyclobutanols: A Clean Access to Alkylrhodium Intermediates Bearing a Quaternary Stereogenic Center

Abstract

The catalytic activation of C-C bonds bears significant ecological and economical advantages. In this account we describe our results for an enantioselective C-C activation of symmetrically substituted tert-cyclobutanols. Subsequent downstream reactions of the obtained alkylrhodium intermediate give rise to a wide range of synthetically versatile products bearing all-carbon quaternary stereogenic centers with excellent enantioselectivities. Intramolecular Bond-Activation Reactions 3.1 Aromatic C(sp 2 )-H Activations 3.2 Aromatic C(sp 2 )-SiR 3 Activations 3.3 1,3-Shift Reactions, C(sp 3

Mn-, Fe-, and Co-Catalyzed Radical Hydrofunctionalizations of Olefins

“…Cramer has also employed the Mukaiyama hydration reaction to the generate cyclobutanols from cyclobutenes. 218 …”

Rhodium‐Catalyzed Regioselective Carboacylation of Olefins: A CC Bond Activation Approach for Accessing Fused‐Ring Systems

“…Four‐membered ring compounds,5 in particular, cyclobutanones and cyclobutenones,6 are privileged substrates for reactions involving the activation and subsequent functionalization of CC bonds 7. 8 Not only are they readily accessible from simple starting materials, such as ketones, olefins, and alkynes,5 their activation, which is driven by strain relief, often does not require temporary9 or permanent directing groups 10.…”

“Cut and Sew” Transformations via Transition-Metal-Catalyzed Carbon–Carbon Bond Activation

“…65b,67 More recently, Auvinet and Harrity extended the scope of the nickel-catalyzed alkyne insertion to include alkynyl boronates (Scheme 46). 68 The regioselectivity of the reaction is influenced by the substituents on the alkynyl boronates: forming regiosomer 73 is favored for alkynyl-bornoates with a sp 3 substituent, whereas those with a sp 2 substituent prefer to give regiosomer 74 .…”