Synthesis of highly strained tetracyclic ketones was achieved by cyclopropanation or epoxidation of tricyclodecenone 1. An unusual formation of α-methoxy β-hydroxy ketone from an α,β-unsaturated enone system via ...Synthesis of highly strained tetracyclic ketones was achieved by cyclopropanation or epoxidation of tricyclodecenone 1. An unusual formation of α-methoxy β-hydroxy ketone from an α,β-unsaturated enone system via Payne rearrangement was reported.展开更多
Nucleophilic additions to endo-tricyclo[5.2.1.0^(2,6)]deca-2(6),8-dien-3-one 4 are described. Experimental results show high preference for exo-facial attack to the enone moiety of tricyclodecadienone. Steric hindra...Nucleophilic additions to endo-tricyclo[5.2.1.0^(2,6)]deca-2(6),8-dien-3-one 4 are described. Experimental results show high preference for exo-facial attack to the enone moiety of tricyclodecadienone. Steric hindrance is the main kinetically controlling factor in the nucleophilic reaction. The shielding effect and the stabilizing effect of the norbornene double bond favor the exo-facial attack also.展开更多
相对于M2M总体服务市场来讲,基于卫星的M2M市场所占比例相对较小。可是,面对未来十年即将到来的数百亿美元的M2M设备市场,基于卫星的M2M设备潜力依然不可小觑。如同NSR在《卫星上M2M and IoT第八版》里所调查的那样,这个市场目前主要被I...相对于M2M总体服务市场来讲,基于卫星的M2M市场所占比例相对较小。可是,面对未来十年即将到来的数百亿美元的M2M设备市场,基于卫星的M2M设备潜力依然不可小觑。如同NSR在《卫星上M2M and IoT第八版》里所调查的那样,这个市场目前主要被Inmarsat以及Iridium、Globalstar等非GEO运营商所占据。过去几年里,针对小卫星商业模式的兴趣和投资相当可观,许多项目都指望前文提及的数百亿美元的M2M/IoT设备能投入使用。尽管如此,NSR并没有看到新的小卫星运营商以强势姿态出现于这个市场。展开更多
文摘Synthesis of highly strained tetracyclic ketones was achieved by cyclopropanation or epoxidation of tricyclodecenone 1. An unusual formation of α-methoxy β-hydroxy ketone from an α,β-unsaturated enone system via Payne rearrangement was reported.
文摘Nucleophilic additions to endo-tricyclo[5.2.1.0^(2,6)]deca-2(6),8-dien-3-one 4 are described. Experimental results show high preference for exo-facial attack to the enone moiety of tricyclodecadienone. Steric hindrance is the main kinetically controlling factor in the nucleophilic reaction. The shielding effect and the stabilizing effect of the norbornene double bond favor the exo-facial attack also.
文摘相对于M2M总体服务市场来讲,基于卫星的M2M市场所占比例相对较小。可是,面对未来十年即将到来的数百亿美元的M2M设备市场,基于卫星的M2M设备潜力依然不可小觑。如同NSR在《卫星上M2M and IoT第八版》里所调查的那样,这个市场目前主要被Inmarsat以及Iridium、Globalstar等非GEO运营商所占据。过去几年里,针对小卫星商业模式的兴趣和投资相当可观,许多项目都指望前文提及的数百亿美元的M2M/IoT设备能投入使用。尽管如此,NSR并没有看到新的小卫星运营商以强势姿态出现于这个市场。
