164171-80-6Relevant articles and documents
Studies on the Lithiation, Borylation, and 1,2-Metalate Rearrangement of O-Cycloalkyl 2,4,6-Triisopropylbenzoates
Mykura, Rory C.,Songara, Pradip,Luc, Eugenia,Rogers, Jack,Stammers, Ellie,Aggarwal, Varinder K.
, p. 11436 - 11441 (2021)
A broad range of acyclic primary and secondary 2,4,6-triisopropylbenzoate (TIB) esters have been used in lithiation-borylation reactions, but cyclic TIB esters have not. We have studied the use of cyclic TIB esters in lithiation-borylation reactions and looked at the effect of ring size (3- → 6-membered rings) on the three key steps of the lithiation-borylation protocol: deprotonation, borylation and 1,2-metalate rearrangement. Although all rings sizes could be deprotonated, the cyclohexyl case was impractically slow, and the cyclopentyl example underwent α-elimination faster than deprotonation at ?78 °C and so could not be used. Both cyclobutyl and cyclopropyl cases underwent rapid borylation, but only the cyclobutyl substrate underwent 1,2-metalate rearrangement. Thus, the cyclobutyl TIB ester occupies a “Goldilocks zone,” being small enough for deprotonation and large enough to enable 1,2-migration. The generality of the reaction was explored with a broad range of boronic esters.
Terminal Trifluoromethylation of Ketones via Selective C-C Cleavage of Cycloalkanols Enabled by Hypervalent Iodine Reagents
Wu, Shuang,Li, Junzhao,He, Ru,Jia, Kunfang,Chen, Yiyun
supporting information, p. 9204 - 9209 (2021/11/30)
We report the first terminal trifluoromethylation at aryl and alkyl ketones' ?, or more remote sites via the selective C-C bond cleavage of cycloalkanols. The noncovalent interactions between alcohols and hypervalent iodines(III) reagents were disclosed to activate both alcohols and the Togni I reagent in the dual photoredox/copper catalysis for the transformation. This reaction was scalable to the gram-scale synthesis, applicable to the structurally complex steroid trifluoromethylation, and extendable to the pentafluoroethylation.
Regioselective Electrochemical Cyclobutanol Ring Expansion to 1-Tetralones
Petti, Alessia,Natho, Philipp,Lam, Kevin,Parsons, Philip J.
supporting information, p. 854 - 858 (2021/01/12)
A mild electrochemical method for the regioselective preparation of 1-tetralones under environmentally friendly conditions from readily available cyclobutanols was developed. A series of aromatic- and heteroaromatic-fused 1-tetralones was accessed through ring expansion of the functionalized cyclobutanols via electrochemical generation of alkoxy radicals and intramolecular cyclization.