Diastereoselective Carbocyclization of 1,6-Heptadienes Triggered by Rhodium-Catalyzed Activation of an Olefinic CH Bond

• Published in: Angewandte Chemie International Edition Vol. 53; no. 16; pp. 4209 - 4212
• Main Authors: Aïssa, Christophe, Ho, Kelvin Y. T., Tetlow, Daniel J., Pin-Nó, María
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 14-04-2014; WILEY‐VCH Verlag
• Subjects: Activation; Activation analysis; Alkadienes - chemistry; Alkenes; Bonding; Catalysis; Communications; Cyclization; CH activation; Derivatives; diastereoselectivity; diene; Folding; Functional groups; Insertion; rearrangement; rhodium; Rhodium - chemistry; Stereoisomerism; CH activation; diastereoselectivity; diene; rearrangement; rhodium
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201400080

The use of α,ω‐dienes as functionalization reagents for olefinic carbon–hydrogen bonds has been rarely studied. Reported herein is the rhodium(I)‐catalyzed rearrangement of prochiral 1,6‐heptadienes into [2,2,1]‐cycloheptane derivatives with concomitant creation of at least three stereogenic centers and complete diastereocontrol. Deuterium‐labeling studies and the isolation of a key intermediate are consistent with a group‐directed CH bond activation, followed by two consecutive migratory insertions, with only the latter step being diastereoselective.
Folding alkenes: Described is the first example of a rhodium(I)‐catalyzed functionalization of an olefinic CH bond with a 1,6‐heptadiene reagent. This carbocyclization is completely diastereoselective and creates at least three stereogenic centers from simple prochiral substrates. The directing group can easily be converted into other functional groups.