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The reaction of a novel trimetallic reagent system consisting of Et2Zn XTi(OPr(super i))3 where X is Cl or OPr(super i) and an alkylmagnesium halide with various enynes is described. The reaction yields the corresponding cyclic organozinc derivatives. The novel trimetallic reagent system offers a method of devising cyclization of enynes with catalytic quantities of Ti and Mg reagents.

A method for the conversion of metallacycles to hydrazulenes was developed based on the radical cyclization of alkenyl iodides and the Zr-promoted bicyclization of enynes. The synthetic method was characterized by the Pd-catalyzed cyclic carbometalation of alkenes and the Ni-catalyzed cyclic addition of alkenylchromiums to aldehydes. The reaction was also followed by alkenyl radical cyclization reactions which led to the formation of (+-)-7-epi-beta-bulnesene and (+-)-beta-bulnesene.

A novel method for net anti-carbometalation of homopropargyl alcholols is described. The scheme is based on the study which shows that syn- and stereorandom-carboalumination products from sigma-hydroxyalkynes can be thermally isomerized to form alkenylalanes that correspond to anti-carboalumination of alkynes. The conditions and mechanisms for the reactions are presented.

Zirconium-catalyzed enantioselective alkylalumination of monosubstituted alkenes was found possible by using polar solvents such as (CH2Cl)2 and noncyclic ethylalumination, partially accompanied by competitive hydroalumination involving a (2-ethyldecyl)alane. The application of CH3CHCl2 or CH2Cl2 instead of (CH2Cl)2 was found to increase the % ee. The scope of the reaction is not limited to ethylalumination.

The reaction of monosubstituted alkenes containing hydrocarbon and heteroatom substituents with Me3Al in the presence of chiral zirconocene catalyst with subsequent oxidation generates 2-methyl-1-alkanols1 in 85% ee yield. Reaction between 1-octene with Me3Al in 1,2-dichloromethane and dichlorobis(1-neomenthylindenyl)-zirconium generates (2R)-2-methyl-1-octanol. Protonolysis of the reaction generates 2-(n-hexyl)-1-octene. The R configuration of 1 matches the four-centered syn Me-Zr addition.

Reactions of alkene-zirconium complexes exhibit their capacity to undergo stereoisomerization leading to nonstereospecific and highly stereoselective processes. These nonconcerted paths proceed through a novel dipolar zirconate species. Reaction of Et2ZrCp2 with (E)- or (Z)-beta-methylstyrene exhibits 98% stereoselectivity but is nonstereospecific. Thermodynamically less stable stereoisomers isomerize to more stable stereoisomers. In addition to E-Z isomerization, there is a possibility for ring expansion through a polar path leading to zirconacyclopentanes.

Titanium alkoxide catalyzes inter-intra cascade carboalumination reactions of dienes and trienes with dialkylaluminum chlorides. The starting dienes do not have chiral centers. Formation of the resulting cyclopentane derivative is trans-selective and that of the cyclohexane derivative is cis-selective relative to the aluminomethyl and R groups. Formation of chain cyclohexane-like transition states help explain stereochemical observations.

Carbopalladation cascade termination via deferred carbonylative esterification regenerates Pd-phosphine catalyst in situ and promotes Pd-catalyzed cyclic carbopalladation of alkyne without premature incorporation of CO. NMR experiments reveal that premature esterification in the reaction is less than 3%. This synthesis helps examine the kinetics of different competing organopalladium reactions and CO insertion rates.