Shouchu Tang

Application of a domino Friedel-Crafts acylation/alkylation reaction to the formal syntheses of (+/-)-taiwaniaquinol B and (+/-)-dichroanone.

An efficient acid-promoted domino Friedel-Crafts (FC) acylation/alkylation reaction has been developed for the construction of the core 6,5,6-ABC tricyclic skeleton of taiwaniaquinoids. The formal total syntheses of diterpenoids (+/-)-taiwaniaquinol B and (+/-)-dichroanone based on this strategy have been achieved.

Iron-catalyzed radical oxidative coupling reaction of aryl olefins with 1,3-dithiane.

An alternative method to an iron-catalyzed radical oxidative cross-coupling reaction followed by 2-chloro-1,3-dithiane and aryl olefins for the synthesis of β-chloro substituent 1,3-dithiane products is presented. The described method has the advantage of mildness of the reaction conditions and tolerates a variety of functional groups. Preliminary mechanistic studies have confirmed the first example of a coupling of 1,3-dithiane with unactivated alkenes that proceeds via an iron-catalyzed oxidative radical intermediate along the reaction pathway.

Bioinspired Collective Syntheses of Iboga-Type Indole Alkaloids

We present the application of a bioinspired collective synthesis strategy in the total syntheses of seven iboga-type indole alkaloids: (±)-tabertinggine, (±)-ibogamine, (±)-ibogaine, (±)-ibogaine hydroxyindolenine, (±)-3-oxoibogaine hydroxyindolenine, (±)-iboluteine, and (±)-ervaoffines D. In particular, tabertinggine and its congeners serve as iboga precursors for the subsequent biomimetic transformations into other iboga-type alkaloids.

Fe-catalyzed direct dithioacetalization of aldehydes with 2-chloro-1,3-dithiane.

Present methods to synthesize 1,3-dithiane molecules require either harsh reaction conditions or highly specialized reagents. We have developed a catalytic dithioacetalization process that directly gains access to the corresponding 1,3-dithianes using aldehydes and 2-chloro-1,3-dithiane in a highly efficient manner. This methodology is beneficial due to mildness of the reaction conditions, and the dithioacetaliation process results in good to excellent yields by using 15 mol % of an iron catalyst.

Metal-Free Difunctionalization of Alkynes with 2-Chlorodithiane for Synthesis of β-Ketodithianes.

Dithianes are versatile umpolung intermediates in organic synthesis but have rarely been employed in radical cross-coupling reactions. Here we describe the oxidative coupling method for alkyne difunctionalization under metal-catalyst-free conditions. The efficient protocol directly affords a variety of β-ketodithianes in good to excellent yields with high regioselectivities. It provides a general pathway for accessing valuable dithianes with controlled formation of a new C-C bond and a C-O bond via a radical coupling pathway.

Di‐tert‐Butyl Peroxide‐Mediated Atom‐Transfer Radical Addition of 2‐Chlorodithiane to Aryl Alkynes under Mild Conditions

Atom transfer radical addition (ATRA) of 2-chlorodithiane onto aryl alkynes through the use of di-tert-butyl peroxide as an oxidant at room temperature directly affords a variety of synthetically valuable β-chloro-(Z)-vinyl dithianes in good yields with high regioselectivities and without the assistance of any transition metals. It provides an operationally simple pathway to access vinyl dithianes with controlled formation of a new C(sp(2) )C bond and a C(sp(2) )Cl bond.

PtCl2‐Catalyzed Tandem Enyne Cyclization/1,2 Ester Migration Reaction Controlled by Substituent Effects of All‐Carbon 1,6‐Enynyl Esters

On the move: A novel PtCl2-catalyzed tandem 1,6-enyne cyclization/1,2-acyloxy migration reaction was developed, which was shown to be controlled by substitution effects. Using this method, a series of substituted enol esters containing the cyclopentenyl motif were prepared in moderate to high yields.

Dithiane Induced Cycloaddition/Aromatization Tactic for the Synthesis of Multisubstituted Furans.

The development of a new transition-metal-free tactic for convergent, one-pot synthesis of multisubstituted furans by β-chloro-vinyl dithiane cyclization with aldehydes is described. Key to the success was the development of a new vinylidene dithiane site as a donor allene that generates the active dihydrofuran, which undergoes in situ aromatization under mild conditions.

Scalable, efficient total synthesis of (+)-mupirocin H

A scalable, efficient total synthesis of mupirocin H was accomplished in 7 longest linear steps with 39% overall yield. The developed strategy is great progress for the construction of pseudomonic acid analogues and all steps in our strategy could be conducted on a gram scale. The strategy is also suitable for other related molecules.

Regiodivergent radical oxidative coupling of vinyl ethers with dithiane by copper or iron catalysis

We disclose a facile, direct, and regiospecific coupling of variously substituted vinyl ethers with dithiane to yield a variety of α-dithianyl aldehydes in good to excellent yields via a copper catalyzed radical process. The procedure is no need for pre-functionalization and is under mild conditions. Additionally, the direct dithioacetalization of vinyl ethers using an iron catalyst for the preparation of 2-substituted dithiane derivatives is also reported.