Asymmetric decarboxylative [3 + 2] cycloaddition for the diastereo- and enantioselective synthesis of spiro[2.4]heptanes via cyclopropanation
Asymmetric decarboxylative [3 + 2] cycloaddition for the diastereo- and enantioselective synthesis of spiro[2.4]heptanes via cyclopropanation
复制标题
通过环丙烷化反应非对映和对映选择性合成螺[2.4]庚烷的不对称脱羧[3 2]环加成
DOI：
10.1039/d2qo00124a
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发表时间：
2022
影响因子：
5.4
通讯作者：
Jitian Liu
中科院分区：
文献类型：
--
作者：
Can Gao;Ting Zhang;Xiaoxun Li;Jing-De Wu;Jitian Liu
不对称环加成反应已成为构建对映体富集分子，特别是具有多环骨架的对映体富集分子的有力而可靠的策略之一。本文报道了在钯配合物和手性脲叔胺的协同催化下，γ-亚甲基-δ-戊内酯与硝基烯烃的不对称脱羧[3 + 2]环加成反应，得到了多种手性螺[2.4]庚烷，产率高，对映选择性高，非对映选择性适中.温和的反应条件，结合良好的官能团耐受性，提供了一个容易获得的多取代的手性螺[2.4]庚烷轴承三个连续的立体中心，包括一个全碳四元立体中心。此外，本研究首次报道了2-硝基苯并呋喃与1，4-偶极子的不对称脱羧和脱芳[3 + 2]反应，以提供复杂的多环支架。该产物的大规模合成和合成转化进一步证明了其合成实用性。
Asymmetric cycloaddition reactions have emerged as one of the powerful and reliable strategies for the construction of enantioenriched molecules, especially those with polycyclic frameworks. Herein, we report the asymmetric decarboxylative [3 + 2] cycloaddition of γ-methylidene-δ-valerolactones with nitroolefins under the cooperative catalysis of a palladium complex and a chiral urea-tertiary amine, delivering a variety of chiral spiro[2.4]heptanes in good yields with high enantioselectivities and moderate diastereoselectivities. The mild reaction conditions, in conjunction with good functional group tolerance, provided an easy access to multisubstituted chiral spiro[2.4]heptanes bearing three contiguous stereogenic centers including an all-carbon quaternary stereocenter. Moreover, this study reports the first asymmetric decarboxylative and dearomative [3 + 2] reaction of 2-nitrobenzofurans with 1,4-dipoles to afford complex polycyclic scaffolds. Large-scale synthesis and synthetic transformations of the product further demonstrate its synthetic utility.