Functional Group Protection: The Lee Synthesis of Jujuyane

A. Venkat Narsaiah of CSIR-Indian Institute of Technology, Hyderabad selectively removed one of the silyl ethers of 1, to give 2 (Tetrahedron Lett. 2021, 82, 153410. DOI: 10.1016/j.tetlet.2021.153410). Andrés G. Santana of the Instituto de Productos Naturales y Agrobiología del CSIC used the proximity of the adjacent carbamate to direct the oxidative removal of one of the three benzyl ethers of 3, leading to 4 (J. Org. Chem. 2021, 86, 16736. DOI: 10.1021/acs.joc.1c01977). Anikó Borbás of the University of Debrecen developed complementary protocols for the reduction of 5 to either regioisomer of 6 (J. Org. Chem. 2021, 86, 12973. DOI: 10.1021/acs.joc.1c01667). Fangfang Li of Central South University and Tao Li and Wanxiang Zhao of Hunan University used diphenylphosphine to demethylate the aryl ether 7 to the phenol 8 (Org. Biomol. Chem. 2021, 19, 7633. DOI: 10.1039/D1OB01286J).

Guang Yang of Nankai University also used diphenylphosphine to convert the sulfonamide 9 to the free amine 10 (Org. Chem. Front. 2021, 8, 6182. DOI: 10.1039/D1QO01190A). Thomas Schaub of BASF showed that tributylphospine catalyzed the addition of the urethane 11 to acetylene, leading to the N-vinylated product 12 (J. Org. Chem. 2021, 86, 13041. DOI: 10.1021/acs.joc.1c01807). Tobias Ritter of the Max-Planck-Institut für Kohlenforschung developed an alternative vinylating reagent (J. Am. Chem. Soc. 2021, 143, 12992. DOI: 10.1021/jacs.1c06632). Yoshio Hisaeda and Hisashi Shimakoshi used electrolysis to convert the amine 13 to the cyanoformamide 14 (J. Org. Chem. 2021, 86, 16134. DOI: 10.1021/acs.joc.1c00837). Yan-Ping Zhu of Yantai University coupled the amine 15 with the α-diazo β-keto ester 16, leading via Wolff rearrangement to the malonylated product 17 (J. Org. Chem. 2021, 86, 17471. DOI: 10.1021/acs.joc.1c02165).

Jiangmeng Ren and Bu-Bing Zeng of the East China University of Science and Technology showed that povidone-iodine was an effective catalyst for converting the aldehyde 18 to the acetal 19 (Tetrahedron 2021, 92, 132250. DOI: 10.1016/j.tet.2021.132250). Nan Li, Meng Deng and Baoming Ji of Luoyang Normal University used a Co catalyst to prepare the carboxylic acid 21 by the deprotection of the allyl ester 20 (Org. Lett. 2021, 23, 8460. DOI: 10.1021/acs.orglett.1c03185). Hua Lu of Peking University showed that in the presence of propylene oxide 23, the amino acid 22 could be converted into the N-carboxyanhydride 24 (Nature Commun. 2021, 12, 5810. DOI: 10.1038/s41467-021-25689-y). Toyonobu Usuki of Sophia University used methanol to protect one of the three alkenes of 25, as the rearranged lactone 26 (Org. Biomol. Chem. 2021, 19, 6038. DOI: 10.1039/D1OB00657F).

The cyclooctanoid sesquiterpene jujuyane (29) was isolated from the cactus Stevia jujuyensis of Argentina. In the course of a synthesis of 29, Hee-Yoon Lee of KAIST protected one of the two alkenes of 27 as the bromo ether 28 (Org. Lett. 2021, 23, 4651. DOI: 10.1021/acs.orglett.1c01391).