5204-84-2Relevant academic research and scientific papers
Copper Hydride Catalyzed Enantioselective Synthesis of Axially Chiral 1,3-Disubstituted Allenes
Bayeh-Romero, Liela,Buchwald, Stephen L.
, p. 13788 - 13794 (2019/09/10)
The general enantioselective synthesis of axially chiral disubstituted allenes from prochiral starting materials remains a long-standing challenge in organic synthesis. Here, we report an efficient enantio- and chemoselective copper hydride catalyzed semireduction of conjugated enynes to furnish 1,3-disubstituted allenes using water as the proton source. This protocol is sufficiently mild to accommodate an assortment of functional groups including keto, ester, amino, halo, and hydroxyl groups. Additionally, applications of this method for the selective synthesis of monodeuterated allenes and chiral 2,5-dihydropyrroles are described.
Enantioselective synthesis of allenes by catalytic traceless petasis reactions
Jiang, Yao,Diagne, Abdallah B.,Thomson, Regan J.,Schaus, Scott E.
supporting information, p. 1998 - 2005 (2017/02/15)
Allenes are useful functional groups in synthesis as a result of their inherent chemical properties and established reactivity patterns. One property of chemical bonding renders 1,3-substituted allenes chiral, making them attractive targets for asymmetric synthesis. While there are many enantioselective methods to synthesize chiral allenes from chiral starting materials, fewer methods exist to directly synthesize enantioenriched chiral allenes from achiral precursors. We report here an asymmetric boronate addition to sulfonyl hydrazones catalyzed by chiral biphenols to access enantioenriched allenes in a traceless Petasis reaction. The resulting Mannich product from nucleophilic addition eliminates sulfinic acid, yielding a propargylic diazene that performs an alkyne walk to afford the allene. Two enantioselective approaches have been developed; alkynyl boronates add to glycolaldehyde imine to afford allylic hydroxyl allenes, and allyl boronates add to alkynyl imines to form 1,3-alkenyl allenes. In both cases, the products are obtained in high yields and enantioselectivities.
An enantioselective synthesis of (R)-5,6-octadecadienoic acid
Yu, Qiong,Ma, Shengming
, p. 1596 - 1601 (2015/03/04)
A convenient, scalable, and highly enantioselective total synthesis of (R)-5,6-octadecadienoic acid was developed by using the recently established ATA (allenylation of terminal alkynes) reaction of TBS-protected (TBS = tert-butyldimethylsilyl) propargyl alcohol with n-dodecanal in the presence of (R)-α,α-diphenylprolinol as the chiral source. The axial chirality of the allene unit withstood the many common organic transformations that were needed to achieve the total synthesis with a high ee (enantiomeric excess) value.
