Enantioselective Synthesis of Pyrrolidine-, Piperidine-, and Azepane-Type <i>N</i>-Heterocycles with α-Alkenyl Substitution: The CpRu-Catalyzed Dehydrative Intramolecular <i>N</i>-Allylation Approach
作者:Tomoaki Seki、Shinji Tanaka、Masato Kitamura
DOI:10.1021/ol203218d
日期:2012.1.20
acid derivatives [(R)- or (S)-Cl-Naph-PyCOOCH2CH═CH2] catalyzes asymmetric intramolecular dehydrative N-allylation of N-substituted ω-amino- and -aminocarbonyl allylic alcohols with a substrate/catalyst ratio of up to 2000 to give α-alkenyl pyrrolidine-, piperidine-, and azepane-type N-heterocycles with an enantiomer ratio of up to >99:1. The wide range of applicable N-substitutions, including Boc, Cbz
The combination of carbaboranylmercuric chloride (new type of bulky Lewis acid) and silver triflate efficiently catalyzes cycloisomerization of 1, 3-dienes at room temperature. The catalytic system gives allyl-substituted azacycles and cycloalkanes in excellent yields with high to complete regioselectivity.
Hg(OTf)<sub>2</sub>-catalyzed Cycloisomerization of Aryl- and Hetero-substituted 1,3-Dienes
We developed Hg(OTf)2-catalyzed Friedel–Crafts-like cycloisomerization of 7-arylhepta-1,3-dienes to give propenyl-substituted tetrahydronaphthalenes in excellent catalytic turnover under very mild conditions. 1,3-Dienyl sulfonamides and 1,3-dienyl alcohols were also efficiently cyclized to afford heterocyclic compounds.