Synthesis of Optically Active 5-Alkoxy-6-methylcyclohex-2-en-1-ones and 4-Alkoxy-5-methylcyclopent-1-enyl Benzoate

Abstract

The reaction of (-)-(1E,3Z)-2-methyl-1-((1S)-1-phenylethoxy)penta-1,3-dien-3-ol benzoate with allyltrimethylsilane in SO2 and in the presence of a catalytic amount of Tf2NTMS gives a silyl sulfinate intermediate that furnishes (-)-(6Z,1'S,4S,5S)-5-methyl-4-(1'-phenylethoxy)octa-1,6-dien-6-yl benzoate after acidic workup. The latter undergoes ring-closing metathesis producing (-)-(2S,3S)-2-methyl-3-((1S)-1-phenylethoxy)cyclopent-5-en-1-yl benzoate. It has been converted also into the corresponding trimethylsilyl enol ether. After oxidation, an enone is obtained that undergoes ring-closing metathesis giving (-)-(5S,6S)-6-methyl-5-((1S)-1-phenylethoxy)cyclohex-2-en-1-one.

The impacts of climate change on local hydrology and low flow frequency in the Geum River Basin, Korea

“…This transformation was routinely performed on 5‐gram scale and provided sufficient quantities of 16 , which might serve as a building block for a variety of trans ‐disposed furan‐containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi⋅LiBr15 produced common intermediate 7 .…”

The impacts of climate change on local hydrology and low flow frequency in the Geum River Basin, Korea

“…This transformation was routinely performed on 5‐gram scale and provided sufficient quantities of 16 , which might serve as a building block for a variety of trans ‐disposed furan‐containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi⋅LiBr15 produced common intermediate 7 .…”

A Convergent Approach for the Synthesis of C14–C26 Fragment of Anticancer Drug Eribulin Mesylate

“…HRMS (ESI): calcd. for C16H24NaO2Si [M+Na] + is 299.1443, found 299.1448.6-(Benzyloxy)-1-(trimethylsilyl)hex-1-yn-3-one(15)…”

Enantioselective Total Synthesis of Amphidinolide F

“…This transformation was routinely performed on 5-gram scale and provided sufficient quantities of 16 which might serve as a building block for a variety of trans -disposed furan-containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi•LiBr [15] produced the common intermediate 7 .…”

“…While we believe both C 18 alcohols 31 and 32 are viable compounds for the synthetic sequence, we proceeded forward with the 18 S isomer 31 [17] for practicality reasons including simplification of NMR spectra. Oxidation of the mixture 31 and 32 with TPAP, NMO followed by reduction with L-Selectride gave the 18 S isomer 31 in high distereoselectivity [15:1 ( 31:32 ), 85% yield over two steps]. After EE protection of alcohol 31 , debenzylation and incorporation of the sulfone moiety at C 15 provided the compound 34 .…”

The impacts of climate change on local hydrology and low flow frequency in the Geum River Basin, Korea

“…This transformation was routinely performed on 5‐gram scale and provided sufficient quantities of 16 , which might serve as a building block for a variety of trans ‐disposed furan‐containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi⋅LiBr15 produced common intermediate 7 .…”

A Convergent Approach for the Synthesis of C14–C26 Fragment of Anticancer Drug Eribulin Mesylate

“…HRMS (ESI): calcd. for C16H24NaO2Si [M+Na] + is 299.1443, found 299.1448.6-(Benzyloxy)-1-(trimethylsilyl)hex-1-yn-3-one(15)…”

Enantioselective Total Synthesis of Amphidinolide F

“…This transformation was routinely performed on 5-gram scale and provided sufficient quantities of 16 which might serve as a building block for a variety of trans -disposed furan-containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi•LiBr [15] produced the common intermediate 7 .…”

“…While we believe both C 18 alcohols 31 and 32 are viable compounds for the synthetic sequence, we proceeded forward with the 18 S isomer 31 [17] for practicality reasons including simplification of NMR spectra. Oxidation of the mixture 31 and 32 with TPAP, NMO followed by reduction with L-Selectride gave the 18 S isomer 31 in high distereoselectivity [15:1 ( 31:32 ), 85% yield over two steps]. After EE protection of alcohol 31 , debenzylation and incorporation of the sulfone moiety at C 15 provided the compound 34 .…”

The impacts of climate change on local hydrology and low flow frequency in the Geum River Basin, Korea

“…This transformation was routinely performed on 5‐gram scale and provided sufficient quantities of 16 , which might serve as a building block for a variety of trans ‐disposed furan‐containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi⋅LiBr15 produced common intermediate 7 .…”

A Convergent Approach for the Synthesis of C14–C26 Fragment of Anticancer Drug Eribulin Mesylate

“…HRMS (ESI): calcd. for C16H24NaO2Si [M+Na] + is 299.1443, found 299.1448.6-(Benzyloxy)-1-(trimethylsilyl)hex-1-yn-3-one(15)…”

Enantioselective Total Synthesis of Amphidinolide F

“…This transformation was routinely performed on 5-gram scale and provided sufficient quantities of 16 which might serve as a building block for a variety of trans -disposed furan-containing natural products. Subsequent silyl protection and removal of the enol benzoate with MeLi•LiBr [15] produced the common intermediate 7 .…”

“…While we believe both C 18 alcohols 31 and 32 are viable compounds for the synthetic sequence, we proceeded forward with the 18 S isomer 31 [17] for practicality reasons including simplification of NMR spectra. Oxidation of the mixture 31 and 32 with TPAP, NMO followed by reduction with L-Selectride gave the 18 S isomer 31 in high distereoselectivity [15:1 ( 31:32 ), 85% yield over two steps]. After EE protection of alcohol 31 , debenzylation and incorporation of the sulfone moiety at C 15 provided the compound 34 .…”