Cis Selective RCM Study to the 14-Membered Cyclic Subunit of Bielschowskysin
作者:Subramanian G. Gramani、Ravi K. Sriramula、Karthik Sekar、Eugene G. Yang、Praveena Battu、Aïcha Kopecky、Martin J. Lear
DOI:10.1021/acs.joc.0c02984
日期:2021.5.7
(Z)-selective ring-closing metathesis (RCM) route to the 14-membered carbocycle of bielschowskysin is detailed using naturally occurring chiral starting materials. Unproductive RCM substrates were attributed to alkyne chelation of the ruthenium catalyst and steric disadvantages within the cembranoid precursors, which was eventually circumvented by using cyclic diol benzylidene protection involving a
13-Step total synthesis of Dendrodolide K following iterative Bartlett–Smith iodocarbonate cyclization
作者:Debendra K. Mohapatra、Karthik Pulluri、Srinivas Gajula、Jhillu S. Yadav
DOI:10.1016/j.tetlet.2015.09.126
日期:2015.11
A convergent total synthesis of Dendrodolide K has been achieved starting from commercially available homoallyl alcohol 17 in 13 longest linear sequence with 18.2% overall yield. The key features of this synthesis are Bartlett–Smith iodocarbonate cyclization reaction for the construction of 1,3-syn centers of the polyol system, Sharpless epoxidation followed by titanocene induced deoxygenation of 2
induction in the iodocarbocyclizationreaction of 4-pentenylmalonate derivatives having a stereogenic center at an allylic or a homoallylic position has been investigated. The iodocarbocyclizationreactions of 3-oxy-4-pentenylmalonate derivatives proceeded with high cis-selectivity through stereoelectronic control of the oxygenated substituent at an allylic position. In the reaction of (S)-2-siloxy-4-pentenylmalonate