Synthesis of Boronates with a Protoilludane Skeleton

In memory of David A. Evans

Abstract

Naturally occurring sesquiterpenes with a protoilludane skeleton are frequently oxygenated at carbon atoms C4 and C8. Boronic acid pinacol esters (BPin) are potential precursors for hydroxy groups at these positions and synthetic methods have now been developed for their preparation. Introduction of a boronate in position C4 was achieved by Cu-catalyzed hydroboration of a photochemically generated cyclobutene precursor, which displayed the complete C₁₅-carbon skeleton of protoilludanes. Introduction of BPin at carbon atom C8 was possible by starting with an alkenyl boronate as precursor in a photochemical transformation. A two-photon reaction cascade allowed for creation of the complete protoilludane skeleton with BPin selectively positioned at C8. Subsequent reactions were studied and the oxidative transformation of the boronates into the respective alcohols was shown.

Key words

borylation - domino reactions - hydroboration - natural products - photochemistry - stereoselective synthesis

• References


Reviews:
• 1a Cheng Y.-Z, Feng Z, Zhang X, You S.-L. Chem. Soc. Rev. 2022; 51: 2145
• 1b Xu G.-Q, Xu P.-F. Chem. Commun. 2021; 57: 12914
• 1c Zhu C, Yue H, Chu L, Rueping M. Chem. Sci. 2020; 11: 4051
• 1d Zhang Z, Zhou Y.-j, Liang X.-W. Org. Biomol. Chem. 2020; 18: 5558
• 1e Okumura M, Sarlah D. Eur. J. Org. Chem. 2020; 1259
• 1f Michelin C, Hoffmann N. ACS Catal. 2018; 8: 12046
• 1g Kärkäs MD, Porco JA. Jr, Stephenson CR. J. Chem. Rev. 2016; 116: 9683
• 1h Bach T, Hehn JP. Angew. Chem. Int. Ed. 2011; 50: 1000
• 1i Hoffmann N. Chem. Rev. 2008; 108: 1052

Selected examples:
• 2a Hoffmann N, Pete J.-P. J. Org. Chem. 1997; 62: 6952
• 2b Hoffmann N, Pete J.-P, Inoue Y, Mori T. J. Org. Chem. 2002; 67: 2315
• 2c Proessdorf J, Jandl C, Pickl T, Bach T. Angew. Chem. Int. Ed. 2022; 61: e202208329
• 2d Stegbauer S, Jandl C, Bach T. Chem. Sci. 2022; 13: 11856

Selected examples:
• 3a Buendia J, Chang Z, Eijsberg H, Guillot R, Frongia A, Secci F, Xie J, Robin S, Boddaert T, Aitken DJ. Angew. Chem. Int. Ed. 2018; 57: 6592
• 3b James MJ, Schwarz JL, Strieth-Kalthoff F, Wibbeling B, Glorius F. J. Am. Chem. Soc. 2018; 140: 8624

Selected examples:
• 4a Wagner PJ, McMahon K. J. Am. Chem. Soc. 1994; 116: 10827
• 4b Nuss JM, Chinn JP, Murphy MM. J. Am. Chem. Soc. 1995; 117: 6801
• 4c Wagner PJ, Smart RP. Tetrahedron Lett. 1995; 36: 5135
• 5a Gilbert A, Bach T. Synlett 2023; 34: in press
• 5b See also: Rauscher N, Næsborg L, Jandl C, Bach T. Angew. Chem. Int. Ed. 2021; 60: 24039
• 6a Zech A, Jandl C, Bach T. Angew. Chem. Int. Ed. 2019; 58: 14629
• 6b Proessdorf J, Zech A, Jandl C, Bach T. Synlett 2020; 31: 1598
• 7 Clericuzio M, Mella M, Toma L, Finzi PV, Vidari G. Eur. J. Org. Chem. 2002; 988

Reviews:
• 8a Cadelis MM, Copp BR, Wiles S. Antibiotics 2020; 9: 928
• 8b Siengalewicz P, Mulzer J, Rinner U. Eur. J. Org. Chem. 2011; 7041
• 8c Abraham W. Curr. Med. Chem. 2001; 8: 583
• 8d Ayer W, Browne L. Tetrahedron 1981; 37: 2199
• 9a Parra A, López A, Díaz-Tendero S, Amenós L, García Ruano JL, Tortosa M. Synlett 2015; 26: 494
• 9b Guisán-Ceinos M, Parra A, Martín-Heras V, Tortosa M. Angew. Chem. Int. Ed. 2016; 55: 6969
• 10 Fawcett A, Biberger T, Aggarwal VK. Nat. Chem. 2019; 11: 117
• 11a Kabalka GW, Hutchins R, Natale NR, Yang DT. C, Broach V. Org. Synth. 1979; 59: 42
• 11b Shreshta ML, Qi W, McIntosh C. J. Org. Chem. 2017; 82: 8359
• 12 For directing group effects in alkene addition reactions, see: Lin C, Shen C. ChemCatChem 2019; 11: 961

For hydroboration reactions of 4-alkenyl-1,3-dioxanes, see:
• 13a Mandal AK. Org. Lett. 2002; 4: 2043
• 13b Sakamoto S, Sakazaki H, Hagiwara K, Kamada K, Ishii K, Noda T, Inoue M, Hirama M. Angew. Chem. Int. Ed. 2004; 43: 6505
• 14a Narzullaev AS, Yunusov MS, Yunusov SY. Chem. Nat. Comp. 1973; 9: 424
• 14b Tori M, Nakashima K, Seike M, Asakawa Y, Wright AD, König GM, Sticher O. Tetrahedron Lett. 1994; 35: 3105
• 15a Coote SC, Bach T. J. Am. Chem. Soc. 2013; 135: 14948
• 15b Grygorenko OO, Moskvina VS, Hryshchuk OV, Tymtsunik AV. Synthesis 2020; 52: 2761
• 15c Scholz SO, Kidd JB, Capaldo L, Flikweert NE, Littlefield RM, Yoon TP. Org. Lett. 2021; 23: 3496
• 15d Liu Y, Ni D, Stevenson BG, Tripathy V, Braley SE, Raghavachari K, Swierk JR, Brown MK. Angew. Chem. Int. Ed. 2022; 61: e202200725
• 16a The compound was prepared from propargylic alcohol according to a known procedure: Meier H, Rose B. J. Prakt. Chem. 1998; 340: 536
• 16b The preparation and handling of the potential carcinogenic should be performed with utmost care and adequate protection.
• 17 Tan Y.-X, Peng P.-Y, Wang Y, Liu X.-L, Ye W, Gao D, Linab G.-Q, Tian P. Chem. Commun. 2021; 57: 9724
• 18 Næsborg L, Jandl C, Zech A, Bach T. Angew. Chem. Int. Ed. 2020; 59: 5656
• 19 Zech A, Bach T. J. Org. Chem. 2018; 83: 3069 ; and references cited therein
• 20a Amrein W, Larsson I.-M, Schaffner K. Helv. Chim. Acta 1974; 57: 2519
• 20b Damschen DE, Merritt CD, Perry DL, Scott GW, Talley LD. J. Phys. Chem. A 1978; 82: 2268
• 20c McGarry PF, Doubleday CA. Jr, Wua C.-H, Staab HA, Turro NJ. J. Photochem. Photobiol. A 1994; 77: 109
• 20d Felber T, Schaefer T, He L, Herrmann H. J. Phys. Chem. A 2021; 125: 5078 ; and references cited therein
• 21a Dilling WL, Tabor TE, Boer FP, North PP. J. Am. Chem. Soc. 1970; 92: 1399
• 21b Peet NP, Cargill RL, Bushey DF. J. Org. Chem. 1973; 38: 1218
• 21c Becker D, Nagler M, Hirsh S, Ramun J. J. Chem. Soc., Chem. Commun. 1983; 371
• 21d Becker D, Nagler M, Sahali Y, Haddad N. J. Org. Chem. 1991; 56: 4537
• 21e Kelly JF. D, Kelly JM, McMurry TB. H. J. Chem. Soc., Perkin Trans. 2 1999; 1933
• 21f Brimioulle R, Bauer A, Bach T. J. Am. Chem. Soc. 2015; 137: 5170
• 21g Poplata S, Bauer A, Storch G, Bach T. Chem. Eur. J. 2019; 25: 8135
• 21h Rigotti T, Schwinger DP, Graßl R, Jandl C, Bach T. Chem. Sci. 2022; 13: 2378
• 22 For the set-up, see: Poplata S, Bach T. J. Am. Chem. Soc. 2018; 140: 3228
• 23 CCDC 2238033 (4), 2238034 (8), 2238036 (9), 2238035 (14a), and 2238032 (14b) contain the supplementary crystallographic data for this paper. The data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/structures
• 24a 7-Methoxy-2,2,4-trimethylindenone, see: Liu Z.-Y, Hu J.-W, Huang C.-H, Huang T.-H, Chen D.-G, Ho S.-Y, Chen K.-Y, Chou P.-T. J. Am. Chem. Soc. 2019; 141: 9885
• 24b Methoxy deprotection, see: Štacková L, Russo M, Muchová M, Orel V, Vítek L, Štacko P, Klán P. Chem. Eur. J. 2020; 26: 13184