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Stereoselective Synthesis of Steroids and Related Compounds, IV. Addition of Cerium Reagents Derived from (Trimethylsilyl)propargyl Bromide to Aldehydes
Author(s) -
Eckenberg Peter,
Groth Ulrich,
Köhler Thomas
Publication year - 1994
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199419940707
Subject(s) - chemistry , reagent , regioselectivity , cerium , bromide , trimethylsilyl , stereoselectivity , propargyl , organic chemistry , selectivity , medicinal chemistry , combinatorial chemistry , catalysis
The addition of (trimethylsilyl)propargylmagnesium bromide ( 9 ) to aldehydes afforded predominantly the allenylic alcohols rac ‐ 10 . The regioselectivity of this addition changes dramatically when organocerium reagents were used for the addition. In this case nearly exclusive formation of the homopropargylic alcohols rac ‐ 8 was observed. Highest selectivity for this process was obtained when cerium(III) isopropoxide ( 13 ) was used as a precursor for the formation of the organocerium reagent.