1996 Fiscal Year Final Research Report Summary
Highly Selective Reactions Useful for Organic Syntheses
| Project/Area Number |
06453130
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Synthetic chemistry
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
MIYAURA Norio Hokkaido Univ., Fac.of Eng., Pro., 工学部, 教授 (10002049)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Yasunori Hokkaido Univ., Fac.of Eng., Research Associate., 工学部, 助手 (30271646)
ISHIYAMA Tatsuo Hokkaido Univ., Fac.of Eng., Associate Pro., 工学部, 助教授 (00232348)
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| Project Period (FY) |
1994 – 1996
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| Keywords | Palladium catalyst / Platinum catalyst / Cross-Coupling Reaction / Arylboronates / Allyboranes / Diboron (4) / Thioboranes / Isomerization |
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| Research Abstract |
The addition of 9-alkylthio-9-borabicyclo [3.3.1] nonanes to terminal alkynes was catalyzed by Pd (PPh3) 4 (3mol%) to produce 9- [(Z) -2-alkylthio-1-alkenyl] -9-BBN derivatives in high yields. The synthetic utility of the reaction was demonstrated by the regio-and stereoselective one-pot synthesis of alkenyl sulfides via the palladium-catalyzed thioboration-cross-coupling sequence.
Tetra (alkoxo) diboron added to alkynes in the presence of a catalytic amount of Pt (PPh3) 4 to provide stereodefined cis-bis (boryl) alkenes. Mechanistic study revealed that the oxidative addition of the B-B bond to Pt (0) complex is an initial step in the platinum (0) -catalyzed diboration of alkynes. The addition of bis (pinacolato) diboron to 1,3-dienes was achieved in the presence of platinum (0) catalyst. The addition to 1,3-butadiene of isopren with Pt (PPh3) 4 regio-and stereoselectively produced (Z) -1,4-bis (boryl) -2-butene at 80ﾟC in toluene. On the other hand, the Pt (dba) 2-catalyzed reaction of the diboron with isoprene exclusively produced (E,E) -1,8-bis (boryl) -3,6-dimethyl-2,6-octadience.
We reported the palladium-catalyzed coupling reaction of the pinacol ester of diboron and aryl halides or triflates, which provides the first one-step procedure for arylboronic esters. The cross-coupling reaction with allyl acetates provided the pinacol esters of allylboronic acids in high yields. The reaction was efficiently catalyzed by Pd (dba) 2 in DMSO at 50ﾟC.
Isomerization of pinacol [(E) -3-alkoxy-1-propenyl] boronates to the corresponding gamma-alkoxy-allyboronates was catalyzed by ruthenium or iridium complexes. The [IrH2 (thf) 2 (PPh2Me) 2] PF6 comlex was recognized to be a most efficient catalyst to selectively provide (E) -gamma-alkoxyallyl-boronates under mild conditions. The reagent can be useful for the diastereoselective synthesis of 1,2-diols from carbonyl compounds.
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