Rhodium-Catalyzed Asymmetric Cycloisomerization and Parallel Kinetic Resolution of Racemic Oxabicycles
作者:Charles C. J. Loh、Matthias Schmid、Robert Webster、Andy Yen、Shabnam K. Yazdi、Patrick T. Franke、Mark Lautens
DOI:10.1002/anie.201604937
日期:2016.8.16
variant is unknown. Reported herein is the first rhodium‐catalyzed asymmetric cycloisomerization of meso‐oxabicyclic alkenes tethered to bridgehead nucleophiles, thus providing access to tricyclic scaffolds through a myriad of enantioselective C−O, C−N, and C−C bond formations. Moreover, we also demonstrate a unique parallel kineticresolution, whereby racemic oxabicycles bearing two different bridgehead
Rhodium-Catalyzed Domino Enantioselective Synthesis of Bicyclo[2.2.2]lactones
作者:Alistair Boyer、Mark Lautens
DOI:10.1002/anie.201101773
日期:2011.8.1
Once, twice, three times a catalyst! A novel domino rhodium(I)‐catalyzed asymmetric transformation of substituted oxabicyclic alkenes into bicyclo[2.2.2]lactones proceeded with good yields (up to 78 %) and excellent stereoselectivity (>97 % ee; see scheme; cod=1,5‐cyclooctadiene, Tf=trifluoromethanesulfonyl). Mechanistic investigations suggest that this process proceeds by rhodium‐catalyzed asymmetric
Rhodium-Catalyzed Enantioselective Isomerization of <i>meso</i>
-Oxabenzonorbornadienes to 1,2-Naphthalene Oxides
作者:Andy Yen、Ken-Loon Choo、Shabnam K. Yazdi、Patrick T. Franke、Robert Webster、Ivan Franzoni、Charles C. J. Loh、Amalia I. Poblador-Bahamonde、Mark Lautens
DOI:10.1002/anie.201700632
日期:2017.5.22
Herein we describe a rhodium-catalyzedenantioselective isomerization of meso-oxabicyclic alkenes to 1,2-naphthalene oxides. These potentially useful building blocks can be accessed in moderate to excellent yields with impressive enantioselectivities. Additionally, experimental findings supported by preliminary computations suggest that ring-opening reactions of bridgehead disubstituted oxabicyclic