Abstract
The key synthetic intermediate (4) of 1β-methylcarbapenems (1-3) was efficiently synthesized by employing highly stereocontrolled Reformatsky reaction (C4-alkylation) of 3-(2-bromopropionyl)-2-oxazolidone derivatives (6) with (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethylJ-2-azetidinone (5) in the presence of zinc dust followed by removal of 2-oxazolidone moieties. The best diastereoselectivity (β:α=95:5) could be realized by uses of sterically crowded achiral 2-oxazolidone derivatives such as 4,4-dimethyl-, 4,4,5,5-tetramethyl, and 4,4-dibutyl-5,5-pentamethylene-2-oxazolidone and higher reaction temperatures (refluxing tetrahydrofuran). The remarkable diastereoselectivities observed for the Reformatsky reactions could be explained by means of the weakly chelating transition state models.
| Original language | English |
|---|---|
| Pages (from-to) | 2801-2820 |
| Number of pages | 20 |
| Journal | Tetrahedron |
| Volume | 47 |
| Issue number | 16-17 |
| DOIs | |
| Publication status | Published - Jan 1 1991 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Biochemistry
- Drug Discovery
- Organic Chemistry
Cite this
Highly stereocontrolled synthesis of the 1β-methylcarbapenem key intermediate by the reformatsky reaction of 3-(2-bromopropionyl)-2-oxazolidone derivatives with a 4-acetoxy-2-azetidinone. / Ito, Yoshio; Sasaki, Akira; Tamoto, Kastumi; Sunagawa, Makoto; Terashima, Shiro.
In: Tetrahedron, Vol. 47, No. 16-17, 01.01.1991, p. 2801-2820.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Highly stereocontrolled synthesis of the 1β-methylcarbapenem key intermediate by the reformatsky reaction of 3-(2-bromopropionyl)-2-oxazolidone derivatives with a 4-acetoxy-2-azetidinone
AU - Ito, Yoshio
AU - Sasaki, Akira
AU - Tamoto, Kastumi
AU - Sunagawa, Makoto
AU - Terashima, Shiro
PY - 1991/1/1
Y1 - 1991/1/1
N2 - The key synthetic intermediate (4) of 1β-methylcarbapenems (1-3) was efficiently synthesized by employing highly stereocontrolled Reformatsky reaction (C4-alkylation) of 3-(2-bromopropionyl)-2-oxazolidone derivatives (6) with (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethylJ-2-azetidinone (5) in the presence of zinc dust followed by removal of 2-oxazolidone moieties. The best diastereoselectivity (β:α=95:5) could be realized by uses of sterically crowded achiral 2-oxazolidone derivatives such as 4,4-dimethyl-, 4,4,5,5-tetramethyl, and 4,4-dibutyl-5,5-pentamethylene-2-oxazolidone and higher reaction temperatures (refluxing tetrahydrofuran). The remarkable diastereoselectivities observed for the Reformatsky reactions could be explained by means of the weakly chelating transition state models.
AB - The key synthetic intermediate (4) of 1β-methylcarbapenems (1-3) was efficiently synthesized by employing highly stereocontrolled Reformatsky reaction (C4-alkylation) of 3-(2-bromopropionyl)-2-oxazolidone derivatives (6) with (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethylJ-2-azetidinone (5) in the presence of zinc dust followed by removal of 2-oxazolidone moieties. The best diastereoselectivity (β:α=95:5) could be realized by uses of sterically crowded achiral 2-oxazolidone derivatives such as 4,4-dimethyl-, 4,4,5,5-tetramethyl, and 4,4-dibutyl-5,5-pentamethylene-2-oxazolidone and higher reaction temperatures (refluxing tetrahydrofuran). The remarkable diastereoselectivities observed for the Reformatsky reactions could be explained by means of the weakly chelating transition state models.
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U2 - 10.1016/S0040-4020(01)87086-1
DO - 10.1016/S0040-4020(01)87086-1
M3 - Article
VL - 47
SP - 2801
EP - 2820
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 16-17
ER -