No abstract

A linear hydrogen-bond acidic (HBA) linear functionalized polymer (PLF), was deposited onto a bare surface acoustic wave (SAW) device to fabricate a chemical sensor. Real-time responses of the sensor to a series of compounds including sarin (GB), dimethyl methylphosphonate (DMMP), mustard gas (HD), chloroethyl ethyl sulphide (2-CEES), 1,5-dichloropentane (DCP) and some organic solvents were studied. The results show that the sensor is highly sensitive to GB and DMMP, and has low sensitivity to HD and DCP, as expected. However, the sensor possesses an unexpected high sensitivity toward 2-CEES. This good sensing performance can’t be solely or mainly attributed to the dipole-dipole interaction since the sensor is not sensitive to some high polarity solvents. We believe the lone pair electrons around the sulphur atom of 2-CEES provide an electron-rich site, which facilitates the formation of hydrogen bonding between PLF and 2-CEES. On the contrary, the electron cloud on the sulphur atom of the HD molecule is offset or depleted by its two neighbouring strong electron-withdrawing groups, hence, hydrogen bonding can hardly be formed.

The ring opening-coupling reaction of cyclopropanols with propargylic carbonates affording synthetically attractive allenyl ketones has been developed. The mechanism involves the ligand-exchange reaction of in situ formed allenyl palladium methoxide with cyclopropanols followed by carbon-carbon bond cleavage and reductive elimination. The reactions proceeded smoothly under mild reaction conditions with Pd(0)/XPhos catalysis in the absence of any external base and displayed a wide scope and application to a steroidal skeleton. The efficiency of chirality transfer and synthetic utility of the allene products have also been demonstrated.

An efficient synthesis of halogen-substituted allenyl ketones via Ag-catalyzed oxidative ring opening of allenyl cyclic alcohols under mild reaction conditions has been achieved. The reaction features a wide substrate scope and excellent regioselectivity. The synthetic potential of the products has been demonstrated by their conversion to stereodefined alkenes and heterocyclic compounds.

Ab is(cycloocta-1,5-diene)nickel-catalyzed highly regio-and (E)-stereoselectivehydrocarboxylation of 2-alkynylanilines under very mild conditions has been developed to afford( E)-[2-(o-aminophenyl)]acrylic acids,w hich coulde asily be converted to (E)-3-alkylidene-2-indolinones with important potential bioactivity. Thes tereoselective syntheses of two biologically active molecules,( E)-3-benzylidene-2-indolinone( chemo-preventive potential in inducing NQO1 activity) and (E)-3-(3-methylbutylidene)-2-indolinone( an atural product isolated from Cimicifuga foetida with cytotoxic activity against HL-60 cells) are presented as examples.