A new synthetic concept was suggested in the chemistry of substituted methylidenemalonates that enables their utilization as 1,2-zwitterionic synthons. This strategy is to generate liquid ionic Ga complexes from methylidenemalonates and GaHal3 with a strict 3/4 composition and then use them in further synthesis. A number of complexes with different metal halides have been synthesized and studied in detail. The unique properties of gallium among all metals have been demonstrated and explained. On the basis of the discovered new class of gallium complexes of methylidenemalonates, a number of novel reactions with acetylenes have been elaborated, which are unknown in the conventional chemistry of methylidenemalonates. The main demonstrated process is a three-component addition to a triple bond involving halide anions, leading to the formation of polyfunctional vinyl halides with high E-selectivity. The mechanism has been studied experimentally in fine detail. Application of specially optimized 71Ga NMR spectroscopy makes it possible to take an in-depth look into the gallium chemistry in a new light. In particular, the key participation of GaHal4 – anions in the occurring transformations has been established.

A new strategy for cascade assembly of substituted indenes and polycyclic lactones based on reactions of donor-acceptor cyclopropanes and styrylmalonates with aromatic aldehydes in the presence of GaCl3 has been developed. The use of GaCl3 makes it possible to principally change the direction of the reaction known in this series of substrates and to perform the process in a multicomponent version. Generation of formal 1,2-zwitterionic intermediates owing to complexation of dicarboxylate groups with GaCl3 is the driving force of the reactions discovered. This method makes it possible to assemble indenylmalonates or indano[1',2':2,3]indano[2,1-b]furan-2-ones in one synthetic stage from readily available starting compounds with high regio- and diastereoselectivity. A mechanism of the reactions has been suggested using the (18) O label in benzaldehyde.

Methods for the selective synthesis of mono ( R PcLnOAc), di ( R Pc 2 Ln), and triphthalo cyanines ( R Pc 3 Ln 2 ) of rare earth metals (Ln = Lu, Er, Eu) from symmetrically substituted 2, 3,9,10,16,17,23,24 octaalkylphthalocyanines R PcH 2 (R = Et, Bu) were developed. The syn thesized complexes were characterized by NMR spectroscopy, mass spectrometry, and elec tronic absorption spectra. The conditions for 1 H NMR spectra recording were optimized. Regularities in changing the spectral properties of the synthesized compounds, depending on the lanthanide nature and the planarity of metal phthalocyanine complexes, were found.Rare earth metals (REM) have high coordination numbers and, hence, can form complexes of different compositions with phthalocyanines. 1-3 The unique physi cochemical properties of these complexes provide wide potentialities for their use in different fields of science and technology. 4-8 Accessibility of the phthalocyanine com plexes is a determining factor for practical use. However, their synthesis often produces a mixture of compounds, which impedes isolation and decreases the yields of target products. Therefore, the development of selective meth ods for the synthesis of lanthanide mono , di , and triphthalocyanines and studies of their structure and prop erties are of great significance.In this work, we studied conditions for the directed synthesis of several symmetric alkyl substituted mono , di , and triphthalocyanine complexes of REM and deter mined their spectral characteristics. The use of free ph thalocyanines as the starting compounds was shown to be more efficient than the use of the corresponding phthalo dinitriles, 9 because the reaction time is shortened sub stantially, isolation and purification become simpler, and, in most cases, the yield of target products increases. Results and DiscussionEthyl and butyl substituted phthalocyanines 1 and 2 were used as phthalocyanine ligands. Earlier, these com pounds were obtained in 21 and 38% yields, respec tively, by the reflux of diethyldiiminoisoindoline in N,N dimethylaminoethanol 10 or dibutylphthalodinitrile in n pentanol in the presence of metallic sodium. 11 It turned out that the reflux of solutions of 4,5 diethyl or 4,5 dibutylphthalodinitriles in isoamyl alcohol in the pres ence of lithium methoxide affords phthalocyanines 1 and 2 in 62-64% yields (Scheme 1). Scheme 1 R = Et (1), Bu (2) Reagents and conditions: i. C 5 H 11 i OH, MeOLi, 130 °С, 5-6 h.Monophthalocyanine complexes 3 and 4 were synthe sized under the conditions similar to the preparation of the tetracrown substituted lanthanide complexes. 12 The * Dedicated to Academician A. L. Buchachenko on the occa sion of his 70th birthday.

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A new strategy for the three-component addition of halide anions and acetylenes to donor-acceptor cyclopropanes (DACs) is presented. This reaction, which occurs with high E selectivity, is promoted by gallium(III) salts and based on the 1,2-zwitterionic reactivity of DACs. It opens up a new group of processes involving DACs. The reaction occurs readily with a broad range of substrates and is tolerant of various functional groups. This methodology makes it possible to assemble highly functionalized vinyl halides, which are very convenient building blocks in organic synthesis. A possible mechanism of this reaction and its stereochemical aspects are discussed in detail.