现成的1,1-二氯-2-炔烃是用于合成多官能化丙二烯的通用原料。它们可以由市售的末端炔烃分两步制备。数个1,1,炔丙基衍生物与官能化的烷基,苄基或烯丙基锌试剂的Cu介导反应仅以S N 2'选择性进行,并可以快速有效地合成官能化的氯代烯。这些氯丙二烯与具有出色S N的功能化芳基镁试剂进行新的Cu I催化的取代反应2的选择性得到三取代的多官能化的烯。官能团耐受性极好,并且对氰基,酮,酯,磷酸酯,三氟甲基和卤素等官能团的耐受性良好。
Copper-Catalyzed Propargylic Substitution of Dichloro Substrates: Enantioselective Synthesis of Trisubstituted Allenes and Formation of Propargylic Quaternary Stereogenic Centers
the desired 1,3‐substitution products. The enantioenriched chloroallenes could be further transformed into the corresponding trisubstituted allenes or terminal alkynes bearing all‐carbon quaternary stereogenic centers, through the copper‐catalyzed enantiospecific 1,1/1,3‐substitutions. The two successive copper‐catalyzed reactions could be eventually combined into a one‐pot procedure and different desired
A copper-catalyzed silylation of propargyldichlorides was developed to access chloro-substituted allenylsilanes under mild reaction conditions. Moreover, enantioenriched chloro-substituted allenylsilanes can be synthesized in moderate to high yields and good enantioselectivities with this protocol.
enantioselective synthesis of axially chiral chloroallenes from the propargylic dichlorides is reported, employing a catalytic amount of easily prepared SimplePhos ligand. Exclusive formation of the desired allenes was observed with good enantioselectivities (ee’s 62–96%). Further transformations to trisubstituted allenes or terminal alkynes with a propargylicquaternary carbon center keep a high level
Synthesis of Polyfunctional Allenes by Successive Copper-Mediated Substitutions
作者:Matthias A. Schade、Shigeyuki Yamada、Paul Knochel
DOI:10.1002/chem.201003273
日期:2011.4.4
versatile starting materials for the synthesis of polyfunctionalized allenes. They can be prepared from commercially available terminal alkynes in a two‐step procedure. The Cu‐mediated reaction of several 1,1‐propargylic derivatives with functionalized alkyl, benzylic, or allylic zinc reagents proceeds exclusively with SN2′ selectivity and allows a rapid and efficient synthesis of functionalized chloroallenes
现成的1,1-二氯-2-炔烃是用于合成多官能化丙二烯的通用原料。它们可以由市售的末端炔烃分两步制备。数个1,1,炔丙基衍生物与官能化的烷基,苄基或烯丙基锌试剂的Cu介导反应仅以S N 2'选择性进行,并可以快速有效地合成官能化的氯代烯。这些氯丙二烯与具有出色S N的功能化芳基镁试剂进行新的Cu I催化的取代反应2的选择性得到三取代的多官能化的烯。官能团耐受性极好,并且对氰基,酮,酯,磷酸酯,三氟甲基和卤素等官能团的耐受性良好。