Regio- and Stereoselectivity of the Intramolecular C-H Insertion by Cyclopropylidenes Bearing a Remote Oxido Substituent

Article abstract of DOI:10.1246/bcsj.60.1715

(ω-Oxidoalkyl)cyclopropylidenes generated from (2,2-dibromo-1-methylcyclopropyl)-CH2-X-(CH2)_n-OH (X=CH2 or O, n=1, 2) by the reaction with methyllithium underwent a regioselective intramolecular insertion into the C-H bond at the δ position to the carbenic carbon.The activation effect of the oxido substituent on the reactivity of C-H bonds is discussed on the basis of (1) the ratio of the insertion products to the rearrangement product allenyl alcohol, and (2) the endo stereoselectivity of the present insertion reactions.