Construction of 4-Vinyl-1,2-oxaphospholane 2-Oxides from Vinyloxiranes and Phosphoryl Diazomethanes

Various 4-vinyl-1,2-oxaphospholane 2-oxides are prepared in good to excellent yields from vinyloxiranes and in situ-generated phosphenes from phosphoryl diazomethanes via the phosphene-induced ring expansion of oxiranes. The reaction is a novel and expeditious strategy for the synthesis of 1,2-oxaphospholane 2-oxide derivatives, featuring ring expansion of readily available starting materials, high atom economy, no catalyst, a fast reaction rate, broad functional group tolerance, high yields, and separable diastereomers.

Recent Advance on Dimethyl Sulfoxide (DMSO) Used as a Multipurpose Reactant

Abstract:

Dimethyl sulfoxide (DMSO) is not only a common and cheap aprotic polar solvent with low toxicity, but also serves as an efficient and multipurpose reactant and has widely been used in organic synthesis. DMSO as an important precursor can effectively introducea broad range of functional fragments into organic molecules, such as -Me, -CH, -CH2, -SMe2, -CH2SMe, -CH2SOMe, -SMe, -SO2Me, -SOMe or as O substituents, and serves as a mild oxidant in organic transformations. Many significant achievements based on DMSO as a synthon in synthetic chemistry have rapidly made over the past several years. To help researchers further understand the recent advances in the field, the review summarizes the applications of DMSO as carbon, sulfur, and oxygen sources and is used as the dual synthon in synthetic transformations.

Recent synthesis of thietanes

Thietanes are important aliphatic four-membered thiaheterocycles that are found in the pharmaceutical core and structural motifs of some biological compounds. They are also useful intermediates in organic synthesis. Various synthetic methods of thietanes have been developed, including inter- and intramolecular nucleophilic thioetherifications, photochemical [2 + 2] cycloadditions, ring expansions and contractions, nucleophilic cyclizations, and some miscellaneous methods. The recently developed methods provide some new strategies for the efficient preparation of thietanes and their derivatives. This review focuses on the synthetic methods to construct thietane backbones developed during 1966 to 2019.

Ring-Opening/Recyclization Cascades of Monoactivated Cyclopropanes

A variety of cyclopropyl aryl ketones undergo uncatalyzed cascade ring-opening/recyclization reactions to generate indenones and fluorenones. In addition, a new strategy to access 3-hydroxyindanones possessing two contiguous stereogenic centers, one of them being an all-carbon quaternary center, was also established. During the course of the investigation, pronounced solvent, temperature, and substituent effects on the product distribution were discovered.

I2-DMSO-H2O: A Metal-Free Combination System for the Oxidative Addition of Alkynes to Access (E)-α-Iodo-β-methylsulfonylalkenes

A simple and green reaction was discovered for iodization-methylsulfoxidation of alkynes to access (E)-α-iodo-β-methylsulfonylalkenes. This is the first report for the synthesis of iodovinyl methylsulfones by employing alkynes to react with molecular iodine (I₂), dimethyl sulfoxide (DMSO), and H₂O. Additionally, this protocol represents a new avenue for utilizing DMSO as the source of the -SO₂Me group and H₂O as the "O" source for the construction of the -SO₂Me group from DMSO, which is a valuable finding.