Progress toward a Rationally Designed, Chemically Powered Rotary Molecular Motor
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- 作者：T. Ross Kelly ; Xiaolu Cai ; Fehmi Damkaci ; Sreeletha B. Panicker ; Bin Tu ; Simon M. Bushell ; Ivan Cornella ; Matthew J. Piggott ; Richard Salives ; Marta Cavero ; Yajun Zhao ; Serge Jasmin
- 刊名：Journal of the American Chemical Society
- 出版年：2007
- 出版时间：January 17, 2007
- 年：2007
- 卷：129
- 期：2
- 页码：376 - 386
- 全文大小：647K
- 年卷期：v.129,no.2(January 17, 2007)
- ISSN：1520-5126
文摘
Building on prototype 1, which achieves 120
of phosgene-powered unidirectional rotation torotamer 6 (see Figure 5 in the full article), 7 was designed to accomplish repeated unidirectional rotation(see Scheme 7). Compound 7 contains an amino group on each blade of the triptycene and a4-(dimethylamino)pyridine (DMAP) unit to selectively deliver phosgene (or its equivalent) to the amine inthe "firing position". The synthesis of 7 is described: the key constructive steps are a benzyne addition toan anthracene to generate the triptycene, a stilbene photocyclization to construct the helicene, and a Stillecoupling to incorporate the DMAP unit. The DMAP unit was shown to regioselectively relay 1,1'-carbonyldiimidazole (but not phosgene) to the proximal amino group, as designed, but rotation of thetriptycene does not occur. Extensive attempts to troubleshoot the problem led to the conclusion that therequisite intramolecular urethane formation, as demonstrated in the prototype (1 
4), does not occur with7 (to give 85) or 97 (to give 100). We speculate that either (i) hydrogen bonding between the hydroxypropylgroup and functionality present in 7 but absent from 1 or (ii) a Bürgi-Dunitz (or similar) interaction involvingthe DMAP (see 106) prevents achievement of a conformation conducive to intramolecular urethaneformation.
of phosgene-powered unidirectional rotation torotamer 6 (see Figure 5 in the full article), 7 was designed to accomplish repeated unidirectional rotation(see Scheme 7). Compound 7 contains an amino group on each blade of the triptycene and a4-(dimethylamino)pyridine (DMAP) unit to selectively deliver phosgene (or its equivalent) to the amine inthe "firing position". The synthesis of 7 is described: the key constructive steps are a benzyne addition toan anthracene to generate the triptycene, a stilbene photocyclization to construct the helicene, and a Stillecoupling to incorporate the DMAP unit. The DMAP unit was shown to regioselectively relay 1,1'-carbonyldiimidazole (but not phosgene) to the proximal amino group, as designed, but rotation of thetriptycene does not occur. Extensive attempts to troubleshoot the problem led to the conclusion that therequisite intramolecular urethane formation, as demonstrated in the prototype (1 4), does not occur with7 (to give 85) or 97 (to give 100). We speculate that either (i) hydrogen bonding between the hydroxypropylgroup and functionality present in 7 but absent from 1 or (ii) a Bürgi-Dunitz (or similar) interaction involvingthe DMAP (see 106) prevents achievement of a conformation conducive to intramolecular urethaneformation.