Palladium/H<sup>+</sup>-cocatalyzed kinetic resolution of tertiary propargylic alcohols
作者:Wanli Zhang、Shengming Ma
DOI:10.1039/c8cc01949e
日期:——
A new approach to not-readily-available opticallyactive tertiary propargylic alcohols through palladium/H+-cocatalyzed carboxylation of racemic tertiary propargylic alcohols with CO and MeOH has been described. Bothenantiomers can be obtained with no less than 90% ee utilizing (R) or (S)-DTBM-Segphos. Various transformations of the opticallyactive alcohols have been demonstrated.
已经描述了通过钯/ H + -外消旋的叔炔丙醇与CO和MeOH的羧化羧化反应来制备尚未得到的旋光性叔炔丙醇的新方法。利用(R)或(S)-DTBM-Segphos,两种对映体都可以以不小于90%的ee获得。已经证明了旋光性醇的各种转化。
Lithium Binaphtholate-Catalyzed Asymmetric Addition of Lithium Acetylides to Carbonyl Compounds
The asymmetric addition of lithium acetylides to carbonylcompounds in the presence of a chiral lithium binaphtholate catalyst was developed. A procedure involving the slow addition of carbonylcompounds to lithium acetylides improved the enantioselectivity. This reaction afforded diverse chiral secondary and tertiary propargylic alcohols in high yields and with good to high enantioselectivities.
Chiral lithium binaphtholate effectively catalyzed the enantioselectivealkynylation of ketones using lithium acetylide as an alkynylating agent. This is the first example of the catalytic enantioselective addition of lithium acetylide to carbonyl compounds without the aid of other metal sources.
Rh‐Catalyzed Reaction of Propargylic Alcohols with Aryl Boronic Acids–Switch from β‐OH Elimination to Protodemetalation
作者:Weiyi Wang、Hui Qian、Shengming Ma
DOI:10.1002/cjoc.202000044
日期:2020.4
It is known that Rh‐catalyzed reaction of propargylic alcohols with aryl metallic reagents undergoes SN2’‐type reaction affording allenes via a sequential arylmetalation and β‐OH elimination process. Here we report a Rh/Ag‐cocatalyzed reaction of propargylic alcohols with organoboronic acids affording stereo‐defined (E)‐3‐arylallylic alcohols via arylmetalation and protodemetalation with a high regio‐
众所周知,炔丙醇与芳基金属试剂的Rh催化反应会经历S N 2'型反应,这是通过顺序的芳基金属化和β-OH消除过程提供的。在此我们报道了炔丙醇与有机硼酸的Rh / Ag催化反应,在非常温和的条件下,通过芳基金属化和原金属脱金属以高区域和立体选择性提供了立体定义的(E)-3-芳基烯丙醇。该反应显示出良好的底物范围以及与合成有用的官能团的相容性,而对于旋光的炔丙醇没有外消旋作用。这种反应还可以扩展为具有显着的区域选择性和排他性E-立体选择性的均丙醇。