A new twist for Stork-Danheiser products enabled by visible light mediated trans-cyclohexene formation; access to acyclic distal enones

Abstract

Herein, we investigate the use of visible light to indirectly drive ring opening in unstrained 6- and 7-membered ring systems via reaction with a transiently generated trans-cycloalkene. Identification of conditions...

Efforts toward Synthetic Photosynthesis: Visible Light-Driven CO2 Valorization

“…They set a precedent for urethane preparation from alkene. Our previous investigations into the photoisomerization of arylcycloalkenes with visible light − led us to conceive of a more suitably basic alkene to generate the reactive electrophilic species in situ under mild conditions: strain-loaded cyclohexenes. When, in the presence of an appropriate photosensitizer, styrenic alkenes are treated to blue light irradiation, they are excited to short-lived biradicals, are granted brief rotational freedom, and rapidly relax down to the ground-state geometrical isomers.…”

Exploiting Visible Light Triggered Formation of trans-Cyclohexene for the Contra-thermodynamic Protection of Alcohols

“…We are particularly interested in the development of molecules that can effectively, and repeatedly, convert photochemical energy to useable ground state potentialan energy “currency” . To this end, we are drawn toward cyclohexene, which is predicted to harvest a large portion of the available photochemical energy, approximately 52 kcal/mol. − Indeed, while transient, its existence has been established . The strained alkene was shown to undergo protonation with strong acids to form a cationic intermediate followed by nucleophilic solvolysis. ,, While strong acids were used, we postulated that much of the strain energy would manifest itself in the form of enhanced basicity and that trans -cyclohexenes could be protonated using much weaker acids, which could be exploited to accomplish synthetic work.…”

Soluble Lanthanides as Mediators of the Stork–Danheiser Transposition Reaction

“…The key organometal addition/transposition steps employed by Stork and Danheiser had originally been described in 1947–1949 by Woods et al, who reported the synthesis of several 3-substituted cyclohexenones v through a sequence of 1,2-addition of Grignard reagents to i , followed by hydrolysis/elimination (Scheme b). Despite Woods’ seminal work, the sequence in Scheme b remains commonly referred to as Stork–Danheiser transposition and has found numerous applications in total synthesis and synthetic methodology …”