Convenient Access to Various 1‐Cyclopropylcyclopropane Derivatives

1‐Bromo‐1‐cyclopropylcyclopropane ( 1 ), which is easily accessible in two steps from methyl cyclopropanecarboxylate, does not form a stable Grignard reagent upon reaction with elemental magnesium, yet it readily undergoes bromine/lithium exchange without rearrangement upon treatment with tert ‐butyllithium in diethyl ether/pentane at –78 °C, and the resulting 1‐lithio‐1‐cyclopropylcyclopropane can be trapped with various electrophiles to give the correspondingly 1‐substituted bicyclopropyl derivatives 10 in yields ranging from 38 to over 90 % (13 examples). The (1‐cyclopropylcyclopropyl)boronate 10m , which is also obtained from the 1‐lithio derivative, has been subjected to Suzuki cross couplings with a number of aryl halides to furnish 1‐aryl‐1,1′‐bicyclopropyl compounds 11 (4 examples, 14–50 % yield), predominantly without rearrangement. Further transformations of 1‐cyclopropylcyclopropanecarbaldehyde ( 10e ) have provided 2‐(1‐cyclopropylcyclopropyl)glycine ( 16 ), ethyl 3‐(1‐cyclopropylcyclopropyl)acrylate ( 17 ), and its cycloadducts with the nitrone 18 and cyclopentadiene 19 , albeit the latter only in poor yield.