Zhengxin Cai

Total synthesis of the terpenoid buddledone A: 11-membered ring-closing metathesis.

The first total synthesis of buddledone A was accomplished in seven steps from methyl ethyl ketone (MEK). The key step in the sequence featured an 11-membered ring formation by ring-closing metathesis.

Studies Directed toward the Synthesis of Hamigeran B: A Catalytic Oxidative Cyclization

An approach to the synthesis of hamigeran B is described. Key steps include a Tius-Nazarov cyclization and a palladium-catalyzed oxidative cyclization of an α-hydroxyenone.

Benzothiazines in Synthesis. A Formal Total Synthesis of Pseudopteroxazole

A formal total synthesis of the antitubercular natural product was accomplished. This work was undertaken to address certain stereochemical problems in our initial synthesis. By using an ester group as a surrogate for a methyl group, we were able to intercept a key intermediate in our first synthesis with better selectivity and greater convergence than had previously been the case.

CH Activation in S-Alkenyl Sulfoximines: An Endo 1,5-Hydrogen Migration†

Intramolecular redox reaction: heating N-alkyl, N-allyl-, and N-benzyl-substituted S-alkenyl sulfoximines under appropriate conditions results in the formation of NH-S-alkyl sulfoximines. The intramolecular redox reaction involves a hydride transfer that occurs by a 6-endo-trig process. The intermediates in the reaction can also give access to four- and six-membered heterocyclic rings and a new class of chiral dienes.