Synthesis of 2,3-Disubstituted Indoles and Benzofurans by the Tandem Reaction of Rhodium(II)-Catalyzed Intramolecular C-H Insertion and Oxygen-Mediated Oxidation.

A highly effective and straightforward method to construct a wide range of functionalized 2,3-disubstituted indoles has been developed. The method involves the tandem reaction of rhodium(II)-catalyzed denitrogenative annulation of triazole-based benzyl anilines and oxygen-mediated oxidative aromatization. The developed method can also be used to synthesize 2,3-disubstituted benzofurans by replacing the benzyl anilines with benzyl phenols.

Tunable and chemoselective syntheses of dihydroisobenzofurans and indanones via rhodium-catalyzed tandem reactions of 2-triazole-benzaldehydes and 2-triazole-alkylaryl ketones.

Two novel rhodium(II)-catalyzed tandem reactions were developed for the synthesis of dihydroisobenzofuran and indanone derivatives from 2-triazole-benzaldehydes and 2-triazole-alkylaryl ketones. Dihydroisobenzofuran derivatives were obtained in good yields with high regioselectivities when alcohols were used as nuclophiles in these reactions, whereas the replacement of the alcohol with water resulted in the diastereoselective formation of highly functionalized indanone derivatives.

Concise stereoselective synthesis of oxaspirocycles with 1-tosyl-1,2,3-triazoles: application to the total syntheses of (±)-Tuberostemospiroline and (±)-stemona-lactam R.

A 4-substituted-1-tosyl-1,2,3-triazole-based stereoselective synthesis of structurally diverse oxaspirocycles is reported. The synthesis involves Rh-catalyzed loss of nitrogen from 4-substituted-1-tosyl-1,2,3-triazoles, Grignard reaction, and a ring-closing metathesis reaction as key steps. By employing readily available and stable 4-substituted-1-tosyl-1,2,3-triazoles as surrogates of diazo compounds and nitrogen sources, two types of oxaspirocycles were obtained.

Development of an expedient intramolecular Pauson-Khand reaction approach to stereoselectively construct the trans-decalin with a C1 quaternary chiral center.

Stereoselective synthesis of the trans-decalin subunit with a defined C1 quaternary chiral center has been achieved by the Pauson-Khand reaction (PKR) as a key step. The developed chemistry offers an alternative to the IMDA reaction that has been used for the syntheses of trans-decalin based biologically active natural products.

Asymmetric total synthesis of (+)-fusarisetin A via the intramolecular Pauson-Khand reaction.

An asymmetic total synthesis of (+)-fusarisetin A has been achieved. The essential to our strategy was the application of the intramolecular Pauson-Khand reaction for the stereoselective construction of the trans-decalin subunit of (+)-fusarisetin A with a unique C16 quarternary chiral center. The developed chemistry offers an alternative to the IMDA reaction that has been used for fusarisetin A, and is applicable to analogue synthesis for biological evaluation.