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 Iodohydroxylation of 1,2-Allenylic Sulfoxides in the Presence of Benzyl Thiol
作者:Minyan Wang、Chunling Fu、Shengming Ma
DOI:10.1002/adsc.201000973
日期:2011.7
The iodohydroxylation of 1,2‐allenyl sulfoxides with iodine in the presence of benzylthiol afforded 3‐hydroxy‐2‐iodo‐2(E)‐alkenyl sulfides in good yields and high regio‐ and stereoselectivities. In this reaction it was observed that the sulfoxide functionality was reduced to sulfide and the water in the reaction mixture plays an important role for the stereoselectivity observed. A mechanism involving