TY  - JOUR
A1  - Krüger, Tobias
A1  - Bramborg, Andrea
A1  - Kelling, Alexandra
A1  - Sperlich, Eric
A1  - Linker, Torsten
T1  - Birch Reduction of Arenes as an Easy Entry to γ-Spirolactones
JF  - European journal of organic chemistry
N2  - A convenient method for the synthesis of γ-spirolactones in only 2–3 steps is described. Birch reduction of inexpensive and commercially available aromatic carboxylic acids in the presence of ethylene oxide affords hydroxy acids, which undergo direct lactonization during work-up. Suitable precursors are methyl-substituted benzoic acids, naphthoic, and dicarboxylic acids. Subsequent hydrogenation proceeds smoothly with Pd/C as catalyst and saturated γ-spirolactones are isolated in excellent yields and stereoselectivities. Thus, up to 3 new stereogenic centers can be constructed as sole diastereomers from achiral benzoic acids. Furthermore, it is possible to control the degree of saturation with Raney nickel or Wilkinson's catalyst to obtain products with 1 double bond. Overall, more than 30 new γ-spirolactones have been synthesized in analytically pure form.
KW  - Arenes
KW  - Birch reduction
KW  - Hydrogenation
KW  - Lactones
KW  - Synthetic methods
Y1  - 2021
U6  - https://doi.org/10.1002/ejoc.202101018
SN  - 1434-193X
SN  - 1099-0690
VL  - 2021
IS  - 46
SP  - 6383
EP  - 6391
PB  - Wiley-VCH
CY  - Weinheim
ER  -