trans-Acetonide Controlled endo-Selective Intramolecular Nitrone−Alkene Cycloaddition of Hept-6-enoses: A Facile Entry to Calystegines, Tropanes, and Hydroxylated Aminocycloheptanes
摘要:
High-yielding endo-selective intramolecular nitrone-alkene cycloaddition (INAC) reactions of hept-6-enoses controlled by a trans-acetonide to give bridged bicyclo[4.2.1]isoxazolidines exclusively are realized for the first time. The cycloadducts were readily transformed into calystegine, tropane, and hydroxylated aminocycloheptane frameworks.
trans-Acetonide Controlled endo-Selective Intramolecular Nitrone−Alkene Cycloaddition of Hept-6-enoses: A Facile Entry to Calystegines, Tropanes, and Hydroxylated Aminocycloheptanes
摘要:
High-yielding endo-selective intramolecular nitrone-alkene cycloaddition (INAC) reactions of hept-6-enoses controlled by a trans-acetonide to give bridged bicyclo[4.2.1]isoxazolidines exclusively are realized for the first time. The cycloadducts were readily transformed into calystegine, tropane, and hydroxylated aminocycloheptane frameworks.
Stereo- and Regioselectivity in an Intramolecular Nitrone-Alkene Cycloaddition of Hept-6-enoses with a<i>trans</i>-Acetonide Blocking Group
作者:Tony K. M. Shing、Wai F. Wong、Taketo Ikeno、Tohru Yamada
DOI:10.1002/chem.200800867
日期:2009.3.2
From sugar to cycloadduct: The effect of the trans‐acetonide blockinggroup and the stereochemistry of the substituents on the regio‐ and stereoselectivity in the intramolecularnitrone–alkenecycloaddition (INAC) reaction of hept‐6‐enoses (see scheme) is reported and studied by using theoretical analysis.