The highly stereoselective synthesis of a series of tetrasubstituted mono- as well as disilylated vinylboronates is reported by using the boron-Wittig approach. The condensation between acylsilanes and gem-diborylalkanes gave the desired tetrasubstituted olefins in good to excellent yield and high stereoselectivity. Also, a series of trisubstituted silylated vinyl MIDA-boronates was synthesized by using the boron-Wittig reaction followed by a transesterification reaction. This methodology allows direct incorporation of B(pin) and TMS groups in the anti-position of the olefin in a highly stereoselective manner. Further, sequential Suzuki coupling reaction with the silylated vinyl boronic esters generated all-carbon tetrasubstituted alkenes, which have been applied in the total synthesis of the anticancer drug Tamoxifen and aggregation-induced luminogen agent TPE-TF17.
Polyhydroxyalkanoates (PHAs) have attracted broad interest as promising sustainable materials to address plastic pollution and resource scarcity. However, the chemical synthesis of stereoregular PHAs via ring-opening polymerization (ROP) has long been an elusive endeavor. In this contribution, we exploited a robust spiro-salen yttrium complex (Y3) as the catalyst to successfully prepare syndiotactic PHAs with diverse pendent groups.
We present a comprehensive account of our efforts directed towards the synthesis of sacubitril, a neprilysin inhibitor used in combination with valsartan and marketed as Entresto™. Our initial approach to the formal synthesis of sacubitril employed a chiral pool strategy, utilizing (S)-pyroglutamic acid as a key building block and Cu(I)-mediated Csp2-Csp3 cross-coupling as a key transformation. Further investigations led to the development of chiral amine transfer (CAT) reagents-based stereoselective synthesis.
Fungal endophytes are recognized as an essential source of bioactive compounds. Besides producing a wide variety of compounds, fungal endophytes can also facilitate a biotransformation process. In this process, endophytes act as an enzyme source to catalyze chemical reactions and modify the structures of bioactive compounds.
A visible light photocatalytic cascade reaction was developed, involving sequential self-[2+2] photodimerization of benzoylacetones, De Mayo reaction, acetalization, and alkoxylation, yielding tetrahydrofurans with high stereoselectivity, three stereogenic centers, and two quaternary carbons, under mild conditions with a cycloaddition-rearrangement strategy. Given the significance of photoreaction and rearrangement in organic chemistry, this method provides a valuable approach for the synthesis of tetrahydrofurans.
Polyhydroxyalkanoates (PHAs) have served as promising alternatives to traditional petroleum-based plastics. Chemical synthesis of stereoregular PHAs via stereocontrolled ring-opening polymerization (ROP) of racemic β-lactones was a desired strategy with a formidable challenge. Herein, we developed a class of DiMeBiPh-salen yttrium complexes that adopted a -α configuration for stereoselective ROP of -β-butyrolactones (-BBL) and -β-valerolactone (-BVL).
