Chiral Phosphoramide-Catalyzed Enantioselective Addition of Allylic Trichlorosilanes to Aldehydes. Preparative Studies with Bidentate Phosphorus-Based Amides
作者:Scott E. Denmark、Jiping Fu、Michael J. Lawler
DOI:10.1021/jo052203h
日期:2006.2.1
that more than one Lewis basic moiety (phosphoramide) is involved in the rate- and stereochemistry-determining step of enantioselectiveallylation, bidentate chiral phosphoramides were developed. Different chiral phosphoramide moieties were connected by tethers of methylene chains of varying length. The rate and enantioselectivity of allylation with allyltrichlorosilane promoted by the bidentate phosphoramides
Regio- and stereoselective SN2′ reaction of an allylic picolinate in the synthesis of LY426965
作者:Yuichi Kobayashi、Kai Yamaguchi、Masao Morita
DOI:10.1016/j.tet.2018.02.045
日期:2018.4
applied to the synthesis of LY426965. Reduction of (R)-6-(PMB-oxy)-3-hexyn-2-ol of 93% ee (PMB = p-MeOC6H4CH2) using Red-Al gave (R,Z)-4-iodo-5-(PMB-oxy)hex-3-en-2-ol, which was later converted to the Me-substituted allylic picolinate by Pd-catalyzed coupling with MeZnI followed by esterification with picolinic acid. Allylic substitution with PhMgBr/Cu(acac)2 proceeded with high anti SN2′ selectivity
用基于ArMgBr的铜试剂对γ,γ-二取代的第二级烯丙基吡啶甲酸二甲酯进行烯丙基取代,从而合成LY426965。使用Red-Al还原93%ee(PMB = p -MeOC 6 H 4 CH 2)的(R)-6-(PMB-oxy)-3-hexyn-2-ol 得到(R,Z)-4-碘-5-(PMB-氧基)己-3-烯-2-醇,其随后通过与MeZnI的Pd催化偶合,然后用吡啶甲酸酯化,转化为Me-取代的烯丙基吡啶甲酸酯。用PhMgBr / Cu(acac)2进行烯丙基取代具有很高的抗S N 2'选择性(99%)。臭氧分解,添加c-Hex-MgBr生成醛,并用哌嗪衍生物进行还原胺化,得到LY426965。
Stereospecific Rhodium-Catalyzed Allylic Substitution with Alkenyl Cyanohydrin Pronucleophiles: Construction of Acyclic Quaternary Substituted α,β-Unsaturated Ketones
作者:Ben W. H. Turnbull、Samuel Oliver、P. Andrew Evans
DOI:10.1021/jacs.5b10270
日期:2015.12.16
toward the synthesis of acyclic quaternary-substituted α,β-unsaturated ketones and thereby provides a new cross-coupling strategy for target directed synthesis. A particularly attractive feature with this process is the ability to directly couple di-, tri- and tetrasubstituted alkenyl cyanohydrin pronucleophiles to prepare the corresponding α,β-unsaturated ketone derivatives in a highly selective manner