Studies on the Regio- and Stereoselectivity of Halohydroxylation of 1,2-Allenyl Sulfides or Selenides
摘要:
It was observed that the halohydroxylation of 1,2-allenyl sulfides or selenides with Br-2 (CuBr2 or NBS) or I-2 and water demonstrated a fairly good regioselectivity (i.e., the C=C bond that is remote from the S or Se atom was halohydroxylated with the halogen atom connecting to the middle carbon atom and the hydroxyl group connecting to the non-S terminal carbon or Se-substituted terminal carbon atom of the allene moiety), leading to the synthesis of synthetically important 3-organosulfur or seleno-2-haloallylic alcohols. The stereoselectivity depends on the nature of X+ and S or Se, showing a Z-selectivity with the matched Lewis acid-base pair.
Studies on highly regio- and stereoselective hydration of 1,2-allenylic sulfoxides
作者:Zhao Fang、Chao Zhou、Chunling Fu、Shengming Ma
DOI:10.1039/c0ob00007h
日期:——
A highlyregio- and stereoselective hydration of 1,2-allenylicsulfoxides in which proton served as the electrophile was reported. Through the X-ray diffraction study, it was concluded that the reaction may proceed via a 5-membered cyclic intermediate following by attack of the −OH at the sulfur atom.
Highly Regio- and Stereoselective Oxidative Hydroacetoxylation of 1,2-Allenylic Sulfoxides via a Different Mechanism
作者:Chao Zhou、Zhao Fang、Chunling Fu、Shengming Ma
DOI:10.1021/jo802755k
日期:2009.4.3
A highlyregio- and stereoselective oxidative hydroacetoxylation of 1,2-allenylicsulfoxides affording 1-sulfonyl-1-alken-3-yl acetates in moderate to good yields was developed. Through the X-ray diffraction study, it was observed that the reaction may proceed via a 5-membered cyclic intermediate and the −OAc attacks the chiral carbon atom, which is different from what was observed in our previous
Highly Regio- and Stereoselective Palladium(0)-Catalyzed Addition of Organoboronic Acids with 1,2-Allenic Sulfones, Sulfoxides, or Alkyl- or Aryl-Substituted Allenes in the Presence of Acetic Acid: An Efficient Synthesis of <i>E</i>-Alkenes
作者:Shengming Ma、Hao Guo
DOI:10.1055/s-2007-983822
日期:2007.9
reaction conditions were established to enable the palladium(0)-catalyzed addition of organoboronicacids with 1,2-allenic sulfones, sulfoxides, or alkyl- or aryl-substituted allenes in the presence of acetic acid. This reaction provides a new way for the stereoselective synthesis of tri- or tetrasubstituted E-alkenes. With arylboronic acids, the reactions of 1,2-allenic sulfones, sulfoxides, and alkyl-substituted
Unique Selectivity of Iodohydroxylation Reaction of Allenyl Phenyl Sulfoxides in Aqueous MeCN. A Stereodefined Synthesis of (<i>E</i>)-2-Iodo-3-hydroxy-1-alkenyl Sulfoxides
作者:Shengming Ma、Qi Wei、Haiming Wang
DOI:10.1021/ol006639p
日期:2000.11.1
Iodohydroxylation reaction of allenyl phenyl sulfoxides with I-2 can smoothly proceed to generate (E)-2-iodo-3-hydroxy-1-alkenyl sulfoxides with excellent regio- and stereoselectivity in high or excellent yields. The configuration of E-2a was determined by the X-ray diffraction study.