Naphthalene Diels-Alder in a self-assembled molecular flask.
Despite its inertness toward pericyclic reactions under common conditions, naphthalenes readily undergo Diels-Alder reactions when coencapsulated with a suitable dienophile within the cavity of a self-assembled host. Localization of the reactant pair significantly reduces the entropic cost of the reaction, and preorganization within the host cavity controls both the regio- and stereoselectivity of the reaction: electronically disfavored exo adducts were obtained, and with substituted naphthalenes, the reaction takes place on the less electron-rich, unsubstituted ring. Our findings highlight the fact that judicious tuning of substrate size and shape within molecular flasks can unveil new and unusual reactivities for otherwise unreactive molecules.
Department of Applied Chemistry, School of Engineering, The University of Tokyo, and CREST, Japan Science and Technology Agency (JST), 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Takashi
T
Murase
Shinnosuke
S
Horiuchi
Makoto
M
Fujita
D018360:Crystallography, X-Ray; D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D009281:Naphthalenes / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D013237:Stereoisomerism
D009281:Naphthalenes; C031721:naphthalene