A dramatic effect of double bond configuration in N-oxy-3-aza Cope rearrangements—a simple synthesis of functionalised allenes
作者:Luis F.V. Pinto、Paulo M.C. Glória、Mário J.S. Gomes、Henry S. Rzepa、Sundaresan Prabhakar、Ana M. Lobo
DOI:10.1016/j.tetlet.2009.02.228
日期:2009.7
The first examples of low temperature N-oxy-3-aza Cope rearrangements, leading to functionalised allenes are described, where the Z-configuration of the enaminic double bond in the rearranging system proves critical.
Total Synthesis of (+)-Sieboldine A: Evolution of a Pinacol-Terminated Cyclization Strategy
作者:Stephen M. Canham、David J. France、Larry E. Overman
DOI:10.1021/jo300872y
日期:2013.1.4
This article describes synthetic studies that culminated in the first total synthesis of the Lycopodium alkaloid sieboldine A. During this study, a number of pinacol-terminated cationic cyclizations were examined to form the cis-hydrindanone core of sieboldine A. Of these, a mild Au(I)-promoted 1,6-enyne cyclization that was terminated by a semipinacol rearrangement proved to be most efficient. Fashioning the unprecedented N-hydroxyazacyclononane ring embedded within the bicyclo[5.2.1]decane-N,O-acetal moiety of sieboldine A was a formidable challenge. Ultimately, the enantioselective total synthesis of (+)-sieboldine A was completed by forming this ring in good yield by cyclization of a protected-hydroxylamine thioglycoside precursor.
Kinetic Resolution of α‐Hydroxy‐Substituted Oxime Ethers by Enantioselective Cu−H‐Catalyzed Si−O Coupling
作者:Xichang Dong、Yuji Kita、Martin Oestreich
DOI:10.1002/anie.201802947
日期:2018.8.13
A catalyst‐controlled enantioselective alcohol silylation by Cu−H‐catalyzed dehydrogenative Si−O coupling of hydroxy groups α to an oxime ether and simple hydrosilanes is reported. The selectivity factors reached in this kineticresolution are generally high (s≈50), and these reactions thereby provide reliable access to highly enantioenriched α‐hydroxy‐substituted oxime ethers. The synthetic usefulness