Heterocycle Construction: The Luo Synthesis of (+)-Lysergol
Gareth J. Pritchard and Marc C. Kimber of Loughborough University devised (Chem. Commun. 2017, 53, 6327. DOI: 10.1039/C7CC03229C) a biomimetic furan synthesis, converting the endoperoxide from the addition of singlet oxygen to 1 to 2. Shou-Fei Zhu and Qi-Lin Zhou of Nankai University prepared (J. Am. Chem. Soc. 2017, 139, 3784. DOI: 10.1021/jacs.6b13168) 4 by the enantioselective reduction of a Rh carbene derived from 3.
Guolin Zhang and Yongping Yu of Zhejiang University developed (Tetrahedron 2017, 73, 2872. DOI: 10.1016/j.tet.2017.03.074) the three-component coupling of the nitro epoxide 5 with the amine 6 and the diester 7 to prepare the pyrrole 8. Sasan Karimi of Queensborough Community College of the City University of New York effected (Tetrahedron Lett. 2017, 58, 2223. DOI: 10.1016/j.tetlet.2017.04.077) the reductive rearrangement of the nitrodiene 9 to the pyrrole 10.
Sampak Samanta of the Indian Institute of Technology Indore coupled (Org. Biomol. Chem. 2017, 15, 3286. DOI: 10.1039/C7OB00240H) the Morita-Baylis-Hillman adduct 11 with 12 to form the pyridine 13. Itaru Nakamura and Masahiro Terada of Tohoku University rearranged (Org. Chem. Front. 2017, 4, 1034. DOI: 10.1039/C6QO00703A) the allene 14 to the pyridine 15. Alexander F. Khlebnikov of Saint Petersburg State University converted (J. Org. Chem. 2017, 82, 5367. DOI: 10.1021/acs.joc.7b00736) the isoxaxole 16 to the pyridine 17. Qiuling Song of Huaqiao University combined (Adv. Synth. Catal. 2017, 359, 952. DOI: 10.1002/adsc.201601386) 18 with the cyclobutanone 19 to make 20.
Akkattu T. Biju of the National Chemical Laboratory established (Angew. Chem. Int. Ed. 2017, 56, 2730. DOI: 10.1002/anie.201611268) that an organocatalyst could mediate the cyclization of 21 to the indole 22. Janakiram Vaitla of the University of Tromso showed (Angew. Chem. Int. Ed. 2017, 56, 4277. DOI: 10.1002/anie.201610520) that 24 could convert an aniline 23 to the indole 25. Arumugam Sudalai, also of the National Chemical Laboratory, observed (J. Org. Chem. 2017, 82, 5940. DOI: 10.1021/acs.joc.7b00439) high regioselectivity in the addition of 26 to the benzyne derived from 27, leading to 28. Such N-sulfonyl indolines are readily converted to the corresponding indoles. Edgar Haak of the Otto-von-Guericke-Universitšt Magdeburg achieved (Synlett 2017, 28, 701. DOI: 10.1055/s-0036-1588124) the direct synthesis of herbindole A (31) by the Ru-mediated condensation of 30 with the alkyne 29.
(+)-Lysergol (34) is a hallucinogenic ergot alkaloid found in the seeds of the morning glory Rivea corymbosa. En route to 34, Tuoping Luo of Peking University assembled (Org. Lett. 2017, 19, 624. DOI: 10.1021/acs.orglett.6b03779) the enantiomerically-pure precursor 32, then used the Miura/Murakami indole synthesis ( 2014, October 20) to convert it to 33.