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Study presents results that correct unambiguously the wrong stereochemical structure attribution of ethyl Z- alpha,alpha-difluoro 4-phenyl-3-butenoate resulting from the addition of the ethyl difluoroacetate radical to phenylacetylene. A novel and efficient method for the stereoselective preparation of pure ethyl E-alpha,alpha-difluoro-4-phenyl-3-butenoate is developed.

The kinetics of the B[F.sub.3]-catalyzed ring-opening reaction of various endo/exo m- and p-substituted diarylhomobenzoquinone epoxides are examined in CD[Cl.sub.3] in order to elucidate the remote [pi]-aryl participation. The studies have shown that the geometrical characteristics of the vacant oxirane Walsh orbital and the cyclobutene antibonding orbital has played a vital role in the topological features of [[eta].sup.2] [pi]-aryl participation.

The application of supercritical carbon dioxide as an environmentally friendly alternative to conventional organic solvents for the synthesis of a variety of carboxylic amides is described. Preliminary experiments with an objective to develop an intramolecular variant of amide synthesis which afford macrolactams indicated that the application of C[O.sub.2]/co-solvent mixtures might offer advantages for the synthesis of large-ring compounds.

An asymmetric synthesis of the potent substance P receptor antagonist (+)-CP-99,994 from 4-phenyl-1-butene is described. The synthesis involved Pd(0)-catalyzed asymmetric allylic and homoallylic C-H diamination.

A two-step procedure is described for preparing 2-alkyl-1,3-butadienes. Cuprate addition to 1,4-dibromo-2-butene has produced 3-alkyl-4-bromo-1-butene, a product of [S.sub.N]2 substitution and dehydrohalogenation has produced 2-alkyl-1,3-butadienes.

The isolation and structural determination of 3,4-diphosphacyclobutenes is reported. The reduction with sodium naphthalenide to give the corresponding ring-opened products through P-P bond cleavage is described.

The reaction of lithium alkyneselenolate with alpha,beta-unsaturated ketone and then alkyl or acyl halide afforded 3-acyl-1-alkyl-2-alkylseleno-1-cyclobutene. Alkylselenocyclobutene and alkylthiocyclobutene were important molecules as a precursor for the preparation of cyclobutenone.