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 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.
Highly regio- and stereoselective four-component iodoamination of Se-substituted allenes. an efficient synthesis of N-(3-organoseleno-2-iodo-2(Z)-propenyl) acetamidesElectronic supplementary information (ESI) available: experimental section. See http://www.rsc.org/suppdata/cc/b3/b300879g/
作者:Shengming Ma、Xueshi Hao、Xian Huang
DOI:10.1039/b300879g
日期:2003.4.16
Z-Selectivity was observed for iodohydroxylation of Se-substituted allenes with I2 and H2O, which is opposite to that of 1,2-allenyl sulfoxides. With n-hexane as the co-solvent Z-iodoamination leading to N-(3-organoseleno-2-iodo-2(Z)-propenyl)acetamide was observed. A brief rational for the stereoselectivity of this reaction is provided.