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The matching and mismatching characteristics of allenylzinc and indium additions to alpha-substituted aldehydes is presented where the reaction has proved to be useful for the synthesis of polyketide natural products.

The preparation of chiral allenylmetal halides is discussed. Results indicate that their addition to aldehydes in situ has afforded anti-homopropargylic alcohol adducts of different ee.

The carboindation of carbon-carbon triple bonds was used to create 1,4-dienols and their halogenated analogues. The presence and position of the hydroxyl group determines whether the resulting structure will be linear or branched.

The stereochemistry of the 1,2-addition of six allylindium reagents to 2- and 3-pyridinecarboxaldehyde and to glyoxylic acid was investigated to determine the course of diastereoselectivity in these coupling reactions. In addition, the competitive intramolecular/intermolecular chelation options that take place during the indium-induced additions under aqueous conditions were examined. Experimental results showed that the ring nitrogen is chelated to the indium atom in the aqueous environment and that there exists a crossover in stereoselectivity with respect to the use of 3-PyCHO.

The synthesis of various gamma-heteroatom-substituted allylindium reagents as well as their reactions with carbonyl compounds were investigated. To this end, the reaction conditions were modified and 1,3-dibromopropene was replaced with 3-bromo-1-iodopropene. Experimental results showed that two types of organoindium complexes, namely, gamma-bromoallylindium and allylic diindium reagents, were produced from the reaction of 1,3-dibromopropene with metallic indium. Gamma-alkoxy-allylindium reagents were synthesized by treating the corresponding gamma-alkoxyallyllithium with indium trichloride.

The rearrangement of substituted epoxides catalyzed by indium(III) chloride was investigated. A simple and efficient method in which aryl-substituted epoxides isomerize with complete regioselectivity to produce a single carbonyl complex via cleavage of benzylic aldehydes and ketones was proposed. Experimental results showed that indium(III) chloride exhibits a high level of efficiency in causing the rearrangement of epoxides to the corresponding carbonyl compounds in a very selective manner.

A series of allyl bromides having an ethereal stereogenic substituent at C-2 were synthesized from methyl acrylate. These were coupled with a number of aldehydes under chromium(II) chloride-mediated conditions to produce syn-4-alkoxyalkan-1-ols in good yield and diastereoselectivity. The effect of changing the nature of the ethereal group and alkyl substituent on the diastereoselectivity of the reaction was also studied. Even when chromium(II) was replaced by indium, syn-4-alkoxyalkan-1-ols was also produced in good yield and diastereoselectivity.

The solvent InCl3 facilitates an anti SE2' transmetallation of alpha-alkoxy allylic stannanes in a solution of EtOAc. This enables them to act as reagents for stereospecific and diastereoselective syn SE2' addition to protected threose and erythrose aldehydes. This was verified in an experiment which yielded several anti adducts which may be used to prepare l-talose, D-allose, L-glucose and D-mannose.

The carboindation of alkenes reveals that the coupling occurs regioselectively at the gamma-carbon of the allylindium reagents through the syn addition process. The regioselectivity associated with the alkynol is found to be dependent on the structure of the alkynol and allylindium. The carbonindation is performed by subjecting the allyndium sesquihalides to smooth allyndation with terminal alkynes having a nearby hydroxyl group at 100 to 140 degrees celcius.

The treatment of N-benzyloxycarbonylamino sulfones with triethyl phosphite catalyzed by In[Cl.sub.3] has produced the corresponding protected [alpha]-amino phosphonates in high yields.

A highly distereoselective allylation of chiral aldimides derived from optically active phenylglycinol mediated by indium metal in alcoholic solvents is demonstrated. Further, a racemization-free protocol for removal of the chiral auxiliary is developed.

An equimolar amount of indium(III) chloride promotes intramolecular allylation of alkynes with allylstannanes. This reaction provides information about the stereochemical aspect of intramolecular allylindation and catalytic use of indium salts.

The indium-mediated radical cyclization reactions of aliphatic iodoalkynes provide a new methodology for multibond formation and enables division of geometrical isomers. The versatility of the reactions was demonstrated by the synthesis of optically active HIV-protease inhibitors.

Research has been conducted on vinyl bromides. Methodology for the stereoselective aryl-substituted gem-bromides reduction to (E)-vinyl bromides has been developed.

Transient chiral allenylindium reagents have been synthesized in situ from enantioenriched propargylic mesylates via oxidative transmetalation. Homopropargylic alcohol compounds were also produced from sequential addition of the iodide and aldehyde to a stirred suspension of indium powder in various solutions. Results showed that the novel synthetic route is highly suitable for the preparation of polypropionate subunits.

Research was conducted to establish a simple and efficient procedure for transesterification catalyzed by indium triiodide. The ester was heated in a specific alcohol in the presence of indium triiodide. The ether extract was washed with sodium thiosulfate and brine and evaporated to produce the product. Results indicate that the procedure using indium triiodide offers a very efficient method for transesterification.

The introduction of an allyl side chain into indium-catalyzed carbon-carbon bond-forming reactions was found to proceed with a synthetically useful stereochemical bias. This is a convenient and reliable method for the stereoselective synthesis of bicyclic gamma-allyl lactones from gamma-hydroxyl precursors. Reliability is due to the capability of a neighboring carboxylic acid group to guide C-C bond creation through chelation to the organometallic species.

A short synthesis of sialic acid in a protected form in two stages with 46% yield from N-acetyl-beta-D-mannosamine is derived from a procedure for the tin- or indium-mediated allylation of unprotected carbohydrates in hydroxylic solvents to a pyranose with an N-acetyl group at C-2. The cost of indium and the generation of indium salts as byproducts in the alkylation reaction restrict this approach.