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The scope of enantioselective cyclopentannelation reaction that uses allenyl ether derived nucleophiles is studied, and two different versatile mechanisms are seen. The results show that for gamma-substituted allene ethers that are axially chiral, very high enantiomeric excesses of cyclopentenone products are observed in the matched cases.

The synthesis and characterization of natural rosephilin by means of an asymmetric cyclopentannelation is described.

Research describes the synthesis of tricyclic hybrid cannabinoids using Trost's metallo-ene reaction and a cation-olefin cyclization. Data indicate that cyclization forms the nonaromatic rings with the proper stereochemistry.

Lithiation of allenyl ethers can be used to create alpha,beta-unsaturated acyl silanes from nonenolizable aldehydes. These compounds are very useful in organic syntheses.

A rapid and direct synthetic pathway to substituted difluorocyclopentenones starting with 2,2,2-trifluoroethanol is described. The method leads to a set of fluorocyclopentenones not available through Ichikawa's approach that uses a Nazarov cyclization to prepare fluorinated cyclopentenones. The synthetic approach developed is aimed at developing convenient means for the synthesis of fluorinated carbanucleosides in future work.

Research was conducted to examine the synthesis of unit A of the cryptophycins from (s)-trans-3-penten-2-ol and from (s)-trans-4-hexen-3-ol using a (2,3)-Wittig rearrangement of a propargyl ether as the key stereodetermining step. The investigation involved the elaboration of the rearrangement product, selective ozonolytic cleavage and Wittig olefination. Results indicate that the introduction of the phenyl group at the end of the sequence provides a convenient access to cryptophycin analogues.

Research was conducted to develop a synthesis of 15-deoxy-12-hydroxy-10-(trifluoromethyl)-Delta-7-alkylidenecyclopentenone prostaglandins-1 methyl ester. The objective was to determine an efficient method for the assembly of the C-100 trifluoromethyl prostanoid. Based on the known structure-activity relationships within this series, the compound is expected to exhibit strong antitumor activity. Synthesis involves the preparation of dieneone via an electrocyclic ring-opening reaction and the ionic electrocyclization which yields the carbon skeleton.

The study of the convergent total synthesis of cryptophycins C and D reveals that the absolute configuration of the alpha-amino acids is identical to the D-series elements. This is confirmed by the correction of the structural assignment for the cryptophycin C. The study indicates that the chloro-O-methyltyrosine unit in the C and A cryptophycins has the D-configuration.

Reverse-phase chromatographic techniques help isolate a solid tumor-selective cytotoxin, mirabimide E, from the blue-green alga Scytonema mirabile. The compound has a tetrachlorinated ethylene group identified as an N-acylpyrrolinone. Spectral studies and stereoselective synthesis of degradation products and total synthesis of mirabimide E help determine the total structure and absolute stereochemistry of the N-acylpyrrolinone. The carbonate ester group influences mirabimide E synthesis.

The synthesis of thebainone-A and beta-thebainone-A was described. The significant features in the synthesis were the regiospecificity of the Diels- Alder reaction between substituted benzoquinone and a diene, the aromatization rearrangement of an alpha-diketone and the formation of a trans-morphinan by intramolecular Michael addition. The preparation was carried out in a total of 24 steps.

An organocatalytic asymmetric Nazarov cyclization of diketoesters is developed that has proceeded by using a dual activation mechanism. The method has produced cyclic products with two adjacent quaternary asymmetric carbon atoms, one of which is an all-carbon stereocenter, with complete or nearly complete diastereoselectivity and in high or very high enantiomeric excess.