Visible-Light-Induced Radical Sulfonylative-Cyclization Cascade of 1,6-Enynol Derivatives with Sulfinic Acids: A Sustainable Approach for the Synthesis of 2,3-Disubstituted Benzoheteroles.

Benzoheteroles are promising structural scaffolds in the realm of medicinal chemistry, but sustainable synthesis of 2,3-difunctionalized benzoheterole derivatives is still in high demand. Indeed, we have conceptually rationalized the intrinsic reactivity of propargylic-enyne systems for the flexible construction of 2,3-disubstituted benzoheteroles through radical sulfonylative-cyclization cascade under organophotoredox catalysis. We hereby report an efficient visible-light-induced sulfonyl radical-triggered cyclization of 1,6-enynols with sulfinic acids under the dual catalytic influence of 4CzIPN and NiBr⋅DME, which led to the formation of 2,3-disubstituted benzoheteroles in good to high yields.

Recent trends in the synthesis and applications of β-iodovinyl sulfones: a decade of progress.

Direct vicinal difunctionalization of π-systems has emerged as a powerful platform for constructing multiple bonds in a single synthetic operation using simple chemical feedstocks. Over the past decade, there has been exponential growth in the direct construction of successive C-S and C-I bonds using a wide variety of sulfonyl and iodide reactants through 1,2-iodosulfonylation of alkynes in a regio- and stereo-selective manner. In this review, we mainly focus on the recent developments in the preparation of β-iodovinyl sulfones and their practical applications in organic synthesis.

Pd(II)-Catalyzed Tandem Cycloannulative-Alkenylation of -Alkynyl-Phenols/Anilines with ()-β-Iodovinyl Sulfones: A Direct Strategy To Construct 3-(Vinyl sulfonyl)benzoheterole Derivatives.

Benzoheteroles and vinyl sulfones are the most promising pharmaceutical relevance motifs, yet the hybrid analogues of these scaffolds still need to be explored. We report herein a general and highly efficient Pd(OAc)-catalyzed intramolecular cyclization and vinylation of -alkynylphenols/-alkynylanilines with ()-β-iodovinyl sulfones under mild reaction conditions. A direct C(sp)-C(sp) cross-coupling is enabled for the diversity-oriented synthesis of vinyl sulfone-tethered benzofurans and indoles in good to high yields with excellent stereoselectivity.

Mn(OAc)-Mediated Unexpected Cycloannulative Sulfonyl Migration Cascade using ()-β-Iodovinyl Sulfones and -Alkynylphenols for Direct Synthesis of Chromene-Derived Vinyl Sulfones.

Cycloannulative sulfonyl migration has received much attention; however, a carbon-to-carbon sulfonyl group shift still needs to be discovered. We hereby report a base-mediated oxa-Michael addition-elimination of ()-β-iodovinyl sulfones with -alkynylphenols, followed by cycloisomerization and unique stereoselective sulfonyl migration in one-pot, is realized under the influence of Mn(OAc)·2HO. A broad range of vinyl sulfone-tethered chromenes were readily accessed in moderate to high yields with good functional group compatibility.

Unified Radical Sulfonylative-Annulation of 1,6-Enynols with Sodium Sulfinates: A Modular Synthesis of 2,3-Disubstituted Benzoheteroles.

Benzoheteroles are valuable scaffolds in medicinal chemistry, but the direct synthesis of 3-vinyl benzoheterole analogues remains unexplored. A rationally designed new class of 1,6-enyne-containing propargylic alcohols has been prepared for the modular synthesis of 3-alkenyl benzoheteroles. Ag-catalyzed cascade radical sulfonylative-cycloannulation of 1,6-enynols with sodium sulfinates is realized to access a wide variety of 2,3-disubstituted benzoheteroles in good to high yields.

Base-mediated [3 + 2]-cycloannulation strategy for the synthesis of pyrazolo[1,5-]pyridine derivatives using ()-β-iodovinyl sulfones.

Pyrazolo[1,5-]pyridines continue to occupy a special place in medicinal chemistry, but the direct construction of 3-sulfonyl analogues remains unexplored. Under basic conditions, pyridinium--amine and the corresponding dipolar aminide played a vibrant role in [3 + 2]-cycloaddition using ()-β-iodovinyl sulfones. KCO-mediated tandem cycloannulative-desulfonylation of ()-β-iodovinyl sulfones with 1-aminopyridinium iodide is realized to access 2-substituted pyrazolo[1,5-]pyridines in good to high yields.

Synthesis and applications of sodium sulfinates (RSONa): a powerful building block for the synthesis of organosulfur compounds.

This review highlights the preparation of sodium sulfinates (RSONa) and their multifaceted synthetic applications. Substantial progress has been made over the last decade in the utilization of sodium sulfinates emerging as sulfonylating, sulfenylating or sulfinylating reagents, depending on reaction conditions. Sodium sulfinates act as versatile building blocks for preparing many valuable organosulfur compounds through S-S, N-S, and C-S bond-forming reactions.

Solvent-Driven Mono- and Bis-sulfenylation of ()-β-Iodovinyl Sulfones with Thiols for Flexible Synthesis of 1,2-Thiosulfonylalkenes and 1,2-Dithioalkenes.

The nature of solvent is a key factor for stereoselective mono- and bis-thiolation of ()-β-iodovinyl sulfones with thiols under basic conditions. A novel and unprecedented vicinal bisthiolation of ()-β-iodovinyl sulfones with thiols under the influence of KCO/DMSO at room temperature for quick assembly of ()-1,2-dithio-1-alkenes is presented. Solvent-induced stereoselective monosulfenylation of ()-β-iodovinyl sulfones with thiols has also been established for the synthesis of both ()- and ()-1,2-thiosulfonylethenes in MeCN and MeOH, respectively.

Recent advances in the synthesis and applications of β-keto sulfones: new prospects for the synthesis of β-keto thiosulfones.

This review mainly focuses on recent developments in the preparation of β-keto sulfones and their extensive synthetic applications. New prospects for the synthesis of β-keto thiosulfones have also been highlighted. Over the last decade, there has been exponential growth in the direct construction of β-keto sulfones using a wide variety of keto and sulfonyl precursors.

Phenylboronic acid-catalyzed tandem construction of S-S and C-S bonds: a new method for the synthesis of benzyl disulfanylsulfone derivatives from S-benzyl thiosulfonates.

A unique phenylboronic acid-catalyzed dimerization-sulfonylation of S-benzyl thiosulfonates has been disclosed. A metal-free tandem construction of S-S and C-S bonds is an operationally simple method to access a wide range of benzyl disulfanylsulfone derivatives in high to excellent yields. Moreover, the robustness of this tandem transformation has been demonstrated by gram-scale reactions, and a plausible mechanism is also proposed.

A straightforward and convenient synthesis of functionalized allyl thiosulfonates and allyl disulfanes.

A practical, highly flexible and eco-friendly method has been developed for the synthesis of allyl thiosulfonates using Morita-Baylis-Hillman (MBH) allyl bromides and sodium arylthiosulfonates, which were readily assembled without any reagent/catalyst. Moreover, the allyl thiosulfonates were successfully transformed into a set of two synthetically viable diallyl disulfanes and unsymmetrical allyl disulfanes in the presence of CsCO. The present protocols are operationally simple and convenient to generate a wide range of functionalized allyl thiosulfonates and allyl disulfanes in good to excellent yields.

Alkynyl Thioethers in Gold-Catalyzed Annulations To Form Oxazoles.

Non-oxidative, regioselective, and convergent access to densely functionalized oxazoles is realized in a functional-group tolerant manner using alkynyl thioethers. Sulfur-terminated alkynes provide access to reactivity previously requiring strong donor-substituted alkynes such as ynamides. Sulfur does not act in an analogous donor fashion in this gold-catalyzed reaction, thus leading to complementary regioselective outcomes and addressing the limitations of using ynamides.

Synthesis of the 1-phenethyltetrahydroisoquinoline alkaloids (+)-dysoxyline, (+)-colchiethanamine, and (+)-colchiethine.

Asymmetric total syntheses of the 1-phenethyl-1,2,3,4-tetrahydroisoquinoline alkaloids (+)-dysoxyline (1), (+)-colchiethanamine (2), and (+)-colchiethine (3) are described. In the synthetic routes, coupling of a key, enatiomerically pure 1-(sulfonylmethyl)tetrahydroisoquinoline with aromatic aldehydes, performed by using the Julia-Kocienski reaction, afforded the corresponding 1-(β-styryl)-substituted tetrahydroisoquinolines with complete retention of the absolute configuration at the C1 carbon atom. Functionalization of the products generated in these processes by using four- or five-step sequences gave the target alkaloids 1-3.

Highly efficient organocatalytic kinetic resolution of activated nitroallylic acetates with aldehydes via conjugate addition-elimination.

A novel, efficient, and unprecedented organocatalytic kinetic resolution has been developed. For the first time, a variety of nitroallylic acetates 1a-i have been resolved with aldehydes in the presence of 2 (2.5 mol %) via conjugate addition-elimination.

Pyrrolidinyl-camphor derivatives as a new class of organocatalyst for direct asymmetric Michael addition of aldehydes and ketones to beta-nitroalkenes.

Practical and convenient synthetic routes have been developed for the synthesis of a new class of pyrrolidinyl-camphor derivatives (7 a-h). These novel compounds were screened as catalysts for the direct Michael addition of symmetrical alpha,alpha-disubstituted aldehydes to beta-nitroalkenes. When this asymmetric transformation was catalyzed by organocatalyst 7 f, the desired Michael adducts were obtained in high chemical yields, with high to excellent stereoselectivities (up to 98:2 diastereomeric ratio (d.

Simple and facile synthesis of tetralone-spiro-glutarimides and spiro-bisglutarimides from Baylis-Hillman acetates.

A simple and convenient synthesis of di(E)-arylidene-tetralone-spiro-glutarimides from Baylis-Hillman acetates via an interesting biscyclization strategy involving facile C-C and C-N bond formation is described. Also, one-pot multistep transformation of the Baylis-Hillman acetates into di(E)-arylidene-spiro-bisglutarimides is presented.

The Baylis-Hillman reaction: a novel source of attraction, opportunities, and challenges in synthetic chemistry.

The Baylis-Hillman reaction is a successful, useful, and atom-economical carbon-carbon bond forming reaction, which has grown from an obscure level to the level of high synthetic popularity due to its operational simplicity and also due to the enormous applications of the Baylis-Hillman adducts in organic synthesis. In this tutorial review, we briefly describe the way this reaction has grown to its present heights and the opportunities, attractions, and challenges the reaction offers with respect to its asymmetric and intramolecular versions, and mechanistic aspects.

TiCl4 catalyzed tandem construction of C-C and C-O bonds: a simple and one-pot atom-economical stereoselective synthesis of spiro-oxindoles.

An atom-economical stereoselective synthesis of [{1-acetyl-5-methyl-6,8-dioxabicyclo(3.2.1)octane}-7-spiro-3'-(indolin-2'-one)] derivatives, containing both the oxindole and 6,8-dioxabicyclo(3.

Simple, facile, and one-pot conversion of the Baylis-Hillman adducts into functionalized 1,2,3,4-tetrahydroacridines and cyclopenta[b]quinolines.

A simple, facile, and one-pot synthesis of functionalized 1,2,3,4-tetrahydroacridines and cyclopenta[b]quinolines from the Baylis-Hillman alcohols, i.e., 2-[hydroxy(2-nitroaryl)methyl]cycloalk-2-enones, is described.