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A Stereoselective Synthesis of 1 $\beta$-Aminocarbapenems.
서경재,이태호,이연영,Seo, Gyeong Jae,Lee, Tae Ho,Lee, Yeon Yeong Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.6
A stereoselective synthesis of $1\beta-aminocarbapenems$ (11a-c) starting from-4-acetoxy-2-axetidinone derivative 4 is described. 4-Acetoxy-2-azetidinone derivative (4) was reacted with lithium enolate of benzophenone limine of glycine phenyl ester (5f) to give alkylated product (R)-6f in good yield with high diastereoselectivity. The alkylated procudt (R)-6f was transformed to thioesters (7a-c) by transesterification with thiols, Thioesters (7a-c) were converted to their oxalimides (8a-c), followed by the phosphite-mediated reductive cyclization to give carbapenems (9a-c). Removal of all protecting groups of carbapenems (9a-c) afforded $1\beta-aminocarbapenems$ (11a-c).
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이중환,고재영,서경재,구양모,이윤영,Lee, Jung Hwan,Ko, Jae Young,Seo, Kyung Jae,Goo, Yang Mo,Lee, Youn Young 대한화학회 1999 대한화학회지 Vol.43 No.4
Allyl (5R)-(Z)- and (5R)-(E)-6-[(2S)-2,3-isopropylidenedioxypropylidene]Penicillanate(10a and 10b) were prepared from allyl (5R)-dibromopenicillanate(6) via a sequence of reactions involving condensation with 2,3-O-isopropylidene-D-glyceraldehyde, reduction with $Zn-NH_4OAc$, and Mitsunobu elimination. Deprotection of isopropylidene and allyl groups of 10a gave potassium (5R)-(Z)-6-[(2S)-2,3-dihydroxypropylidene]penicillanate(4). However, deprotection of isopropylidene group of 10b afforded ${\alpha},\;{\beta}$-unsaturated-lactone(12). Allyl (5R)-(Z)- and (5R)-(E)-6-[(2S)-2-(t-butyldimethlsilyloxy)propylidene]penicillanate(18a and 18b) were prepared from ally (5R)-dibromopenicillanate(6) via a sequence of reactions involving condensation with (2S)-2-(t-butyldimethylsilyloxy)propanal(15), reduction with $Zn-NH_4OAc$ and Mitsunobu elimination or mesylation-elimination. Deprotection of t-butyldimethylsilyl and allyl groups of 18a and 18b gave potassium (5R)-(Z)- and (5R)-(E)-6-[(2S)-2-hydroxypropylidene]penicillanate(5a and 5b), respectively. Allyl (5R)-dibromopenicillanate(6)의 2,3-O-isopropylidene-D-glyceraldehyde와의 축합, $Zn-NH_4OAc$에 의한 환원 및 Mitsunobu 제거반응의 일련의 과정을 거처서 allyl (5R)-(Z) 및 (5R)-(E)-6-[(2S)-2,3-isopropylidenedioxypropylidene]penicillanate(10a 및 10b)를 합성하였다. 화합물10a의 이소프로필리덴 및 알릴 보호기를 제거하여 potassium (5R)-(Z)-6-[(2S)-2,3-dihydroxypropylidene]penicilla-nate(4)를 얻었다. 그러나 화합물 10b의 이소프로필리덴 보호기를 제거한 결과 ${\alpha},\;{\beta}$-unsaturated-lactone(12)이 얻어짐을 확인하였다. Allyl(5R)-6,6-dibromopenicillanate(6)의 (2S)-2-(t-butyldimethyl-silyloxy)propanal(15)과의 축합, $Zn-NH_4OAc$에 의한 환원 및 Mitsunobu 제거반응 또는 메실화-제거반응의 일련의 과정을 거처서 allyl (5R)-(Z)- 및 (5R)-(E)-6-[(2S)-2-(t-butyldimethylsilyloxy)propylidene]-penicillanate(18a 및 18b)를 합성하였다. 화합물 18a 및 18b의 t-부틸디메틸실릴 및 알릴 보호기를 제거하여 potassium (5R)-(Z)- 및 (5R)-(E)-6-[(2S)-2-hydroxypropylidene]penillanate(5a 및 5b)를 얻었다.
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