Sulfoxide-Directed Intramolecular [4 + 2] Cycloadditions between 2-Sulfinyl Butadienes and Unactivated Alkynes

Base-Induced Sulfoxide-Sulfenate Rearrangement of 2-Sulfinyl Dienes for the Regio- and Stereoselective Synthesis of Enantioenriched Dienyl Diols

The base-induced [2,3]-sigmatropic rearrangement of a series of enantiopure 2-sulfinyl dienes has been examined and optimized using a combination of NaH and ⁱPrOH. The reaction takes place by allylic deprotonation of the 2-sulfinyl diene to give a bis-allylic sulfoxide anion intermediate that after protonation undergoes sulfoxide-sulfenate rearrangement. Different substitution at the starting 2-sulfinyl dienes has allowed us to study the rearrangement finding that a terminal allylic alcohol is determinant to achieve complete regioselectivity and high enantioselectivities (90:10-95:5) with the sulfoxide as the only element of stereocontrol. Density functional theory (DFT) calculations provide an interpretation of these results.

Stereoselective Synthesis of Tricyclic β-Lactam by Sulfoxide-Directed Oxidative Lactonization from an Accessible Cephalosporin Intermediate

Tricyclic β-lactam antibiotics show significant antibacterial activities against carbapenem-resistant Enterobacterales (CREs), but the synthesis of a key intermediate for tricyclic β-lactam antibiotics requires eight steps from penicillin with a low total yield of 3% via non-stereoselective lactone formation. Here we report the stereoselective synthesis of the tricyclic β-lactam core by sulfoxide-directed oxidative lactonization from an accessible and inexpensive commercially available cephalosporin intermediate in 23% total yield in six steps.

Polymer-supported eosin Y as a reusable photocatalyst for visible light mediated organic transformations

Rapid synthesis of highly stable polymer-supported eosin Y for visible light-driven photoxidation of thioethers to sulfoxides and phenylboronic acids to phenols.

Sulfinyl-Mediated Stereoselective Overman Rearrangements and Diels-Alder Cycloadditions

Sulfinyl trichloroacetamides are readily obtained in excellent yields through a highly stereoselective Overman rearrangement. Related bis-allylic substrates lead to amido 2-sulfinyl butadiene derivatives in excellent yields, with total chemo- and diastereoselectivity. These amido dienyl sulfoxides undergo highly selective Diels-Alder cycloadditions with N-phenylmaleimide with remarkable stereocontrol by the sulfoxide moiety.

Synthesis of Enantiopure 3-Hydroxypiperidines from Sulfinyl Dienyl Amines by Diastereoselective Intramolecular Cyclization and [2,3]-Sigmatropic Rearrangement

The highly diastereoselective base-promoted intramolecular cyclization of a variety of enantiopure sulfinyl dienyl amines provides novel sulfinyl tetrahydropyridines that are readily converted to 3-hydroxy tetrahydropyridines via sigmatropic rearrangement. The influence of N- and C- substituents on the process has been studied. Procedures to shorten the sequence such as the tandem cyclization followed by [2,3]-sigmatropic rearrangement, as well as cyclization of the free amine, under Boc- or ArSO- deprotection conditions have been examined. Good to excellent levels of selectivity are generally observed for the reported transformations (dr: 75/25 to >98/2). A novel protocol to access substituted amino dienyl sulfoxides is also reported.

Recent advances in stereoselective synthesis of 1,3-dienes

The aim of this review is to present the latest developments in the stereoselective synthesis of conjugated dienes, covering the period 2005-2010. Since the use of this class of compounds is linked to the nature of their appendages (aryls, alkyls, electron-withdrawing, and heterosubstituted groups), the review has been categorized accordingly and illustrates the most representative strategies and mechanisms to access these targets.