139167-17-2Relevant articles and documents
Oxidative Ring Expansion of Cyclobutanols: Access to Functionalized 1,2-Dioxanes
Lapez, Mara-A Marta-N,Jamey, Nicolas,Pinet, Alexis,Figadeìre, Bruno,Ferri, Laurent
supporting information, p. 1626 - 1631 (2021/03/08)
Cyclobutanols undergo an oxidative ring expansion with Co(acac)2 and triplet oxygen to give 1,2-dioxanols. The formation of an alkoxy radical drives the regioselective cleavage of the ring on the more substituted side before insertion of molecular oxygen. The reaction is particularly effective on secondary cyclobutanols but works also on certain tertiary alcohols. Further substitution with neutral nucleophiles under catalytic Lewis acid conditions led to original 1,2-dioxanes with a preferred 3,6-cis-configuration.
A Concise and Enantioselective Approach to Cyclobutanones by Tandem Asymmetric Epoxidation and Enantiospecific Ring Expansion of Cyclopropylidene Alcohols. An Enantiocontrolled Synthesis of (+)- and (-)-α-Cuparenones
Nemoto, Hideo,Ishibashi, Hiroki,Nagamochi, Masatoshi,Fukumoto, Keiichiro
, p. 1707 - 1712 (2007/10/02)
A tandem Katsuki-Sharpless asymmetric epoxidation and enantiospecific ring expansion of 2-alkyl(or 2-aryl)-2-cyclopropylideneethanols (1a-i) afforded chiral 1-alkyl(or 1-aryl)-1-(hydroxymethyl)cyclobutanones (3a-i) in high yields and high enantiomeric excess.These compounds are potentially valuable synthons for the enantioselective creation of the quaternary carbons.Hence, this enabled us to accomplish a concise and enantioselective total synthesis of both (+)- and (-)-cuparenones (11).
