Spirolactones from Dirhodium(II)-Catalyzed Diazo Decomposition with Regioselective Carbon-Hydrogen Insertion
摘要:
Dirhodium(II) caprolactamate, Rh-2(cap)(4), catalyzes diazo decomposition of cycloalkylmethyl diazoacetates which form spirolactones in moderate to high yield by insertion into a tertiary carbon-hydrogen bond. Similar results are obtained with diazoacetates derived from tetrahydropyran-2-methanol and tetrahydrofurfuryl alcohol but not from cyclopropylmethanol. With tetrahydrofuran-3-ylmethyl diazoacetate, Rh-2(cap)(4) catalysis promotes delta-lactone formation via insertion into the oxygen-activated secondary C-H bond instead of gamma-lactone formation by carbene insertion into the unactivated tertiary C-H bond. However, when both 1,5- and 1,6-positions are activated for insertion by adjacent oxygen atoms, as in (2,2-dimethyl-1,3-dioxolan-4-yl)methyl diazoacetate, five-membered ring formation occurs exclusively in Rh-2(cap)(4)-catalyzed reactions, whereas use of dirhodium(II) acetate leads to both insertion products.
Spirolactones from Dirhodium(II)-Catalyzed Diazo Decomposition with Regioselective Carbon-Hydrogen Insertion
摘要:
Dirhodium(II) caprolactamate, Rh-2(cap)(4), catalyzes diazo decomposition of cycloalkylmethyl diazoacetates which form spirolactones in moderate to high yield by insertion into a tertiary carbon-hydrogen bond. Similar results are obtained with diazoacetates derived from tetrahydropyran-2-methanol and tetrahydrofurfuryl alcohol but not from cyclopropylmethanol. With tetrahydrofuran-3-ylmethyl diazoacetate, Rh-2(cap)(4) catalysis promotes delta-lactone formation via insertion into the oxygen-activated secondary C-H bond instead of gamma-lactone formation by carbene insertion into the unactivated tertiary C-H bond. However, when both 1,5- and 1,6-positions are activated for insertion by adjacent oxygen atoms, as in (2,2-dimethyl-1,3-dioxolan-4-yl)methyl diazoacetate, five-membered ring formation occurs exclusively in Rh-2(cap)(4)-catalyzed reactions, whereas use of dirhodium(II) acetate leads to both insertion products.
Conversion of Azides into Diazo Compounds in Water
作者:Ho-Hsuan Chou、Ronald T. Raines
DOI:10.1021/ja407822b
日期:2013.10.9
compounds are in widespread use in synthetic organic chemistry but have untapped potential in chemical biology. We report on the design and optimization of a phosphinoester that mediates the efficient conversion of azides into diazo compounds in phosphate buffer at neutral pH and room temperature. High yields are maintained in the presence of common nucleophilic or electrophilic functional groups, and reaction
Chemodivergent Staudinger Reactions of Secondary Phosphine Oxides and Application to the Total Synthesis of LL–D05139β Potassium Salt
作者:Wenjun Luo、Fang Xu、Zhenguo Wang、Jiyan Pang、Zixu Wang、Zhixiu Sun、Aiyun Peng、Xiaohui Cao、Le Li
DOI:10.1002/anie.202310118
日期:2023.10.9
Unprecedented chemodivergent Staudinger reactions of secondary phosphine oxides (SPO) have been developed. Reagent-controlled 1- or 2-nitrogen atom exclusions from azides have been achieved. Conversion of a chiral SPO to a phosphinic amide was stereoretentive, and the potassium salt of natural product LL-D05139β was synthesized for the first time.
Indolization of <i>N</i>-Aryl Tertiary Amines with Diazoacetates by a Single Organophotocatalyst
作者:Wei Li、Jie Qiu、Hengyuan Li、Wanli Chen、Cheng Hou、Huaifeng Li
DOI:10.1021/acs.orglett.3c01288
日期:2023.5.26
research has focused on using metal carbene reactivity or the innate nucleophilicity of the diazoacetates to create indoles through a traditional two-electron pathway. However, these strategies are constrained by the need for transition metals, oxidants, or substrate prefunctionalization. To overcome the limitations, we report herein an open-shell strategy that utilizes the radical reactivity of diazoacetates
Spirolactones from Dirhodium(II)-Catalyzed Diazo Decomposition with Regioselective Carbon-Hydrogen Insertion
作者:Michael P. Doyle、Alexey B. Dyatkin
DOI:10.1021/jo00115a018
日期:1995.5
Dirhodium(II) caprolactamate, Rh-2(cap)(4), catalyzes diazo decomposition of cycloalkylmethyl diazoacetates which form spirolactones in moderate to high yield by insertion into a tertiary carbon-hydrogen bond. Similar results are obtained with diazoacetates derived from tetrahydropyran-2-methanol and tetrahydrofurfuryl alcohol but not from cyclopropylmethanol. With tetrahydrofuran-3-ylmethyl diazoacetate, Rh-2(cap)(4) catalysis promotes delta-lactone formation via insertion into the oxygen-activated secondary C-H bond instead of gamma-lactone formation by carbene insertion into the unactivated tertiary C-H bond. However, when both 1,5- and 1,6-positions are activated for insertion by adjacent oxygen atoms, as in (2,2-dimethyl-1,3-dioxolan-4-yl)methyl diazoacetate, five-membered ring formation occurs exclusively in Rh-2(cap)(4)-catalyzed reactions, whereas use of dirhodium(II) acetate leads to both insertion products.