Organic Chemistry Portal
Organic Chemistry Highlights

Monday, September 18, 2017
Douglass F. Taber
University of Delaware

Carbon-Carbon Bond Formation: The She Synthesis of Lycopodine

Paul Knochel of the Ludwig Maximilians University Munich transformed (Synlett 2016, 27, 1715. DOI: 10.1055/s-0035-1561934) the inexpensive vinyl ether 2 into a carbon nucleophile that added to 1 to form 3. Yohei Shimizu and Motomu Kanai of the University of Tokyo added (Org. Lett. 2016, 18, 2276. DOI: 10.1021/acs.orglett.6b00914) 5 to 4 to give 6 with high diastereocontrol. Hiroshi Tanaka of the Tokyo Institute of Technology prepared (Eur. J. Org. Chem. 2016, 3478. DOI: 10.1002/ejoc.201600392) 10 by coupling 8 and 9 sequentially with each end of 7. Keary M. Engle of Scripps/La Jolla coupled (J. Am. Chem. Soc. 2016, 138, 14705, DOI: 10.1021/jacs.6b08850; 15122, DOI: 10.1021/jacs.6b09170) 12 and 13 with 11 to give 14.

In a rare example of an intramolecular Julia reaction, Sergey V. Pronin, also of Scripps/La Jolla, assembled (J. Am. Chem. Soc. 2016, 138, 12316. DOI: 10.1021/jacs.6b06847) 17 by adding 15 to 16. Yan Zhang and Gangguo Zhu of Zhejiang Normal University established (Adv. Synth. Catal. 2016, 358, 3730. DOI: 10.1002/adsc.201600623) conditions for the net rearrangement of the terminal epoxide 18 to an aldehyde followed by condensation with 19, leading to 20. James L. Gleason of McGill University devised (Angew. Chem. Int. Ed. 2016, 55, 11557. DOI: 10.1002/anie.201606480) an organocatalyst that mediated the Cope rearrangement of 21 to the aldehyde 22. Amir H. Hoveyda of Boston College developed (Angew. Chem. Int. Ed. 2016, 55, 13210. DOI: 10.1002/anie.201608087) a Mo catalyst for the Z-selective cross metathesis of 23 with 24 to give 25. Robert H. Grubbs of Caltech also reported (J. Am. Chem. Soc. 2016, 138, 14039. DOI: 10.1021/jacs.6b08387) Z-selective cross metathesis (not illustrated), and Philip Wheeler of Materia summarized (Org. Process Res. Dev. 2016, 20, 1182. DOI: 10.1021/acs.oprd.6b00138) effective protocols for removing the Ru residue from metathesis products.

Professor Knochel also described (Org. Lett. 2016, 18, 4778. DOI: 10.1021/acs.orglett.6b02119) the diastereoselective coupling of 26 with 27 to give 28. Doug E. Frantz of the University of Texas at San Antonio prepared (Org. Lett. 2016, 18, 3937. DOI: 10.1021/acs.orglett.6b01904) the alkyne 30 from the triflate 29.

Shenming Ma of the Shanghai Institute of Organic Chemistry assembled (Org. Chem. Front. 2016, 3, 1705. DOI: 10.1039/C6QO00489J) the allene 33 by coupling the boronic acid 32 with the carbonate 31. Benjamin List of the Max-Planck-Institut für Kohlenforschung added (Angew. Chem. Int. Ed. 2016, 55, 8962. DOI: 10.1002/anie.201603649) 35 to 34 to give the allene 36 in high ee and de.

Lycopodine (40) is representative of the Lycopodium alkaloids. En route to 40, Xuegong She of Lanzhou University added (Org. Lett. 2016, 18, 4328, DOI: 10.1021/acs.orglett.6b02072; 4682, DOI: 10.1021/acs.orglett.6b02322) propargyl bromide 38 in a conjugate sense to 37 to give 39.

D. F. Taber, Org. Chem. Highlights 2017, September 18.