Palladacycle-Catalyzed Reaction of Bicyclic Alkenes with Terminal Ynones: Regiospecific Synthesis of Polysubstituted Furans
摘要:
A new synthetic strategy to access polysubstituted furans regiospecifically has been developed using simple bicyclic alkenes and terminal ynones as starting materials with palladacycles as unique active catalysts. A rational mechanism has also been proposed. This reaction features mild reaction conditions, easily available starting materials and palladacycle catalysts, a wide substrate scope, and high regiospecificity.
A fine addition! A highlyenantioselective and efficient procedure for the amino‐alcohol–zinc‐catalyzedaddition of trimethylsilylacetylene to aromatic, α,β‐unsaturated, and aliphatic aldehydes has been developed (see scheme; R=aryl, alkynyl, or alkyl; TMS=trimethylsilyl; TBDMS=tert‐butyldimethylsilyl). The present protocol was successfully applied in the concise synthesis of the natural products marine
很好的补充!已开发出一种高度对映选择性和高效的程序,用于氨基醇锌催化的三甲基甲硅烷基乙炔加成到芳族,α,β-不饱和和脂肪族醛中(见方案; R =芳基,炔基或烷基; TMS =三甲基甲硅烷基; TBDMS =叔丁基二甲基甲硅烷基)。本协议已成功地应用于天然产物海洋炔醇和法卡林二醇的简明合成中。
Rhodium(I)-Catalyzed [4+1] Cycloaddition Reactions of α,β-Unsaturated Imines with Terminal Alkynes for the Preparation of Pyrrole Derivatives
作者:Akio Mizuno、Hiroyuki Kusama、Nobuharu Iwasawa
DOI:10.1002/anie.200904402
日期:2009.10.19
Rhodium vinylidene intermediates are characteristic for the title reaction (see scheme; coe=cyclooctene, cy=cyclohexyl). This reaction proceeds by the nucleophilic addition of the nitrogen atom of the imine to the rhodium vinylidene complex to give a zwitterionic intermediate, which undergoes intramolecular cyclization to afford the corresponding pyrrole.
Catalytic enantioselective addition of terminal alkynes to aromatic aldehydes using zinc-hydroxyamide complexes
作者:Gonzalo Blay、Luz Cardona、Isabel Fernández、Alícia Marco-Aleixandre、M. Carmen Muñoz、José R. Pedro
DOI:10.1039/b911592g
日期:——
A mandelamide ligand, derived from (S)-mandelic acid and (S)-phenylethanamine, catalyzes the addition of aryl-, alkyl- and silyl-alkynylzinc reagents to aromatic and heteroaromatic aldehydes with good yields and good to high enantioselectivities.
Metal-free synthesis of activated ynesulfonamides and tertiary enesulfonamides
作者:Lucile Andna、Laurence Miesch
DOI:10.1039/c9ob00947g
日期:——
An operationally simple synthesis of activated ynesulfonamides and enesulfonamides is described. Ynesulfonamides can be obtained through reaction of sulfonylamides with activated bromoalkynes and Triton B in a short time at room temperature. Likewise, terminal alkynes react with sulfonylamides to provide enesulfonamides. Z/E enesulfonamides can be transformed exclusively into E enesulfonamides.
Modification of the Fritsch–Buttenberg–Wiechell rearrangement: a facile route to unsymmetrical butadiynes
作者:Erin T Chernick、Sara Eisler、Rik R Tykwinski
DOI:10.1016/s0040-4039(01)01901-3
日期:2001.12
echell rearrangement has been used to form unsymmetrically substituted 1,3-butadiynes from 1,1-dibromo-olefin precursors. The reaction proceeds via lithium–halogen exchange, followed by migration of the aryl or alkynyl moiety to provide the butadiyne framework. The facile formation of the dibromo-olefins in three steps from commercially available aryl aldehydes or carboxylic acid chlorides makes this