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Two-dimensional (2D) layered nanosheets of violet phosphorene (VP) have great potential in optoelectronic applications owing to their unique electronic, mechanical, and optical properties. Herein, the nonlinear optical (NLO) properties of liquid-phase-exfoliated (LPE) VP nanosheets based on a side-polished D-shaped fiber (DSF) were experimentally investigated by a homemade dual-balance detection fiber system at the near-infrared band. A strong saturable absorption response was observed. The corresponding modulation depth and saturation intensity were determined as ∼1.57 and ∼68.1 MW/cm2, respectively. As an application, a VP-DSF saturable absorber mode-locked erbium-doped fiber laser was realized for the first time, generating ultrashort pulses with a pulse width of 799 fs. Moreover, the stable soliton molecule mode-locking pulses with a pulse width and time interval of 816 fs and 20.5 ps, respectively, were obtained by adjusting the polarization state in the same laser cavity. The experimental results demonstrated the potential use of VP-based nanomaterials in ultrafast photonics applications. [ABSTRACT FROM AUTHOR]

In this report, the originally proposed rupestonic acid (5) and pechueloic acid (3) were efficiently synthesized. The chiral lactone 13, recycled from the degradation of saponin glycosides, was utilized to prepare the key chiral fragment 11. During the exploration of this convergent assembly strategy, the ring-closing metathesis (RCM), SmI2-prompted intermolecular addition, and [2,3]-Wittig rearrangement proved to be effective transformations for the synthesis of subunits. [ABSTRACT FROM AUTHOR]

Herein, we describe a highly effective 1,8-conjugate-addition-mediated formal (3+3)-annulation of (aza)- para -quinone methides in situ generated from propargylic alcohols with 4-hydroxycoumarins and 1,3-dicarbonyl compounds under the catalysis of a Brønsted acid. This methodology affords efficient and practical access to synthetically important and highly functionalized pyranocoumarins and pyrans in excellent yields under mild conditions. Importantly, these products exhibit impressive inhibitory activity toward α-glucosidase.

An efficient and straightforward Lewis-acid-mediated stereoselective (4 + 3)-cyclization of indole-substituted alkylidene malonates and donor-acceptor cyclopropanes has been developed involving the Friedel-Crafts/Michael addition cyclization cascade. This reaction provides a mild and effective method for the construction of synthetically and structurally interesting functionalized cycloheptannelated indoles.