Cyclopropenyllithiums as a new source of 1,1-bismetalated cyclopropyl derivatives

Abstract

The allylmetalation of functionalised cyclopropenyllithium derivatives leads to the unique formation of 1,1-bismetalated cyclopropyl species that react selectively with different electrophiles.

Recent advances in the syntheses, transformations and applications of 1,1-dihalocyclopropanes

“…37 The allyl metallation of cyclopropenyllithium 67 gave bismetallated cyclopropane moiety 68 which on further reaction with I 2 under acidic conditions afforded the corresponding diiodocyclopropane 69 (Scheme 28). The reaction of bismetallated cyclopropane species with iodine afforded gem-diiodocyclopropanes.…”

Carbometallation Reactions

“…The latter are represented as monomeric species with M 1 and M 2 metal atoms in view of the fact that the exact structure of the bismetallic center has not been confirmed yet (leaving the possibility either for Mg, Zn or Zn, Zn attached Formation of gem-bismetallated species by intermolecular allylmetallation of cyclopropenyllithium substrates [29].…”

“…The transmetallation reaction of the bismetallated species 107 into an organocopper was completed using Me 2 CuCNLi 2 and subsequent S N 2 reaction with allyl bromide (108d). ACP derivatives 108f and 108g could also be prepared by treatment of the bismetallated species with either alkylidenemalonate or an aldehyde [29]. As a logical extension, the diastereoselectivity of the allylzincation of functionalized cyclopropenyllithium derivatives 110 was examined.…”

“…of iodine, followed by an acidic hydrolysis. Product 111c with two different electrophile moieties on the cyclopropyl core was obtained [29]. In contrast to the formation of metallated cyclopropyl rings, straightforward approaches to the stereoselective preparation of metallated cyclobutane species appeared to be relatively rare [30].…”

“…Cyclopropenyllithium could also be considered as a new entry to diastereoselective polysubstituted bismetallated cyclopropyl derivatives. Indeed, it has been reported [29] that cyclopropenyllithium species 106 easily obtained from 1,1,2-tribromocyclopropane 105 are able to generate gem-bismetallated cyclopropane derivatives (Scheme 10.32).…”