10.1002/anie.202014581
Angewandte Chemie International Edition
COMMUNICATION
ꢀ=ꢁ,7480=ꢁ,8/ꢁ9<2,89-9<984.ꢁ,.4/=ꢁ,<0ꢁA4/06Cꢁ,@,46,-60ꢂꢁ=>,-60ꢁ &ꢄ =ꢁ.,8ꢁ-0ꢁ.98@0<>0/ꢁ48>9ꢁαꢅ,7489><416?9<9-9<,>0=ꢁ-Cꢁ><0,>708>ꢁ
=>,<>482ꢁ 7,>0<4,6=ꢂꢁ >34=ꢁ ,::<9,.3ꢁ 9110<=ꢁ ,8ꢁ 9:0<,>498,66Cꢁ =47:60ꢁ A4>3ꢁ ,ꢁ ꢐ<428,</ꢁ <0,208>ꢁ 9<ꢁ :9>,==4?7ꢁ -9<93C/<4/0ꢁ 19669A482ꢁ ,ꢁ
,::<9,.3ꢁ19<ꢁ>30ꢁ/4<0.>ꢁ:<0:,<,>498ꢁ91ꢁ,74/0=ꢁ1<97ꢁ9<2,89-9<984.ꢁ =96@08>ꢁ 0B.3,820ꢃꢁ &34=ꢁ :<9.0/?<0ꢁ .9?6/ꢁ -0ꢁ ,::640/ꢁ >9ꢁ &ꢄ =ꢁ
,.4/=ꢁ,8/ꢁ,7480=ꢃꢁꢄ>ꢁ.97:60708>=ꢁ9B4/,>4@0ꢁ,7489.,<-98C6,>498=ꢁ 9->,480/ꢁ,1>0<ꢁ.<9==ꢅ.9?:6482ꢁ/4<0.>6Cꢁ9<ꢁ>9ꢁꢑꢀ&=ꢂꢁ-Cꢁ><0,>482ꢁ>307ꢁ
91ꢁ-9<984.ꢁ,.4/=ꢂꢁ48.6?/482ꢁ>30ꢁA9<5ꢁ91ꢁ'?ꢁ98ꢁ,7489.,<-98C6,>498ꢁ A4>3ꢁ ,ꢁ /4110<08>ꢁ ,7480ꢁ >9ꢁ :<9@4/0ꢁ >30ꢁ .9<<0=:98/482ꢁ &ꢄ ꢂꢁ ,8/ꢁ
91ꢁ 9<2,89-9<984.ꢁ ,.4/=ꢁ A4>3ꢁ ꢀꢅ.369<9,7480=ꢁ ?8/0<ꢁ 3423ꢁ ꢆ"ꢁ =?-=0;?08>6Cꢁ.98@0<>482ꢁ>307ꢁ>9ꢁ>30ꢁαꢅ,7489><416?9<9-9<,>0ꢃꢁ&34=ꢁ
:<0==?<0ꢃ ꢇꢈ ꢁꢀ6>0<8,>4@06Cꢂꢁ ꢉ4,9ꢁ ,8/ꢁ .9ꢅA9<50<=ꢁ <0:9<>0/ꢁ >30ꢁ ,669A0/ꢁ 19<ꢁ>30ꢁ :<0:,<,>498ꢁ 91ꢁ αꢅ,7489><416?9<9-9<,>0=ꢁ ꢊ%.3070ꢁ
,7489.,<-98C6,>498ꢁ 91ꢁ9<2,89-9<984.ꢁ ,.4/=ꢁ A4>3ꢁ =47:60ꢁ ,7480=ꢁ ꢒ,ꢋꢁ A4>39?>ꢁ 4=96,>498ꢁ 91ꢁ ,8Cꢁ 48>0<70/4,>0=ꢃꢁ '0ꢁ 3,@0ꢁ =39A8ꢁ
ꢇ
?=482ꢁ "ꢇꢁ ,=ꢁ ,8ꢁ 9B4/,8>ꢃ
ꢁ)3,82ꢁ ,8/ꢁ ,ꢁ <0:9<>0/ꢁ >30ꢁ :<0@49?=6Cꢁ>3,>ꢁαꢅ,7489><416?9<9-9<,>0=ꢁ.,8ꢁ-0ꢁ3C/<96CD0/ꢁ48>9ꢁαꢅ
,7489.,<-98C6,>498ꢁ 91ꢁ -9<984.ꢁ ,.4/=ꢁ 48ꢁ ,ꢁ ꢆ"ꢁ ,>79=:30<0ꢁ A4>3ꢁ ,7489-9<984.ꢁ ,.4/=ꢁ ?=482ꢁ %4ꢆ6ꢒꢁ 9<ꢁ .98@0<>0/ꢁ 48>9ꢁ ,7480=ꢁ -Cꢁ
ꢆ?"ꢁ ,=ꢁ >30ꢁ 9B4/,8>ꢃ ꢇꢇ ꢁꢄ<,8:99<ꢁ ,8/ꢁ .9ꢅA9<50<=ꢁ <0:9<>0/ꢁ >30ꢁ /0-9<C6,>498ꢁA4>3ꢁ)<ꢊ"ꢅ#<ꢋꢒꢁꢊ%.3070ꢁꢒ-ꢋꢃꢒꢁ
!4.506ꢅ.,>,6CD0/ꢁ ,7489.,<-98C6,>498ꢁ 91ꢁ -9<984.ꢁ ,.4/=ꢁ ?=482ꢁ
ꢆ<ꢊꢆ"ꢋꢌꢁ,=ꢁ>30ꢁ.,<-98C6ꢁ=9?<.0ꢃꢇꢍꢁ
ꢁ
ꢄ8ꢁ=?77,<CꢂꢁA0ꢁ3,@0ꢁ/0@069:0/ꢁ,ꢁ80Aꢁ70>39/ꢁ19<ꢁ>30ꢁ=C8>30=4=ꢁ
91ꢁ,<97,>4.ꢁ,8/ꢁ,6508C6ꢁꢑꢀ&=ꢃꢁ&30ꢁ19<7,6ꢁ.,<-98C6,>498ꢁ91ꢁA4/06Cꢅ
,@,46,-60ꢁ-9<984.ꢁ,.4/=ꢁ,8/ꢁ>304<ꢁ/0<4@,>4@0=ꢂꢁ-9<984.ꢁ,.4/ꢁ:48,.96ꢁ
0=>0<=ꢁ 9<ꢁ :9>,==4?7ꢁ 9<2,89><416?9<9-9<,>0=ꢁ ,669A=ꢁ 19<ꢁ >30ꢁ
:<0:,<,>498ꢁ 91ꢁ ꢑꢀ&=ꢁ >3,>ꢁ A0<0ꢁ 89>ꢁ ,..0==4-60ꢁ :<0@49?=6Cꢁ ,8/ꢁ
1,.464>,>0=ꢁ,..0==ꢁ>9ꢁ7,8Cꢁ.97798ꢁ=><?.>?<0=ꢃꢁ&30ꢁꢑꢀ&=ꢁ9<ꢁ&ꢄ =ꢁ
9->,480/ꢁ ,1>0<ꢁ >30ꢁ .<9==ꢅ.9?:6482ꢁ <0,.>498ꢁ .9?6/ꢁ -0ꢁ /4<0.>6Cꢁ
.98@0<>0/ꢁ48>9ꢁ,74/0=ꢂꢁαꢅ,7489><416?9<9-9<,>0=ꢂꢁαꢅ,7489-9<984.ꢁ
,.4/=ꢂꢁ9<ꢁ,7480=ꢃꢁꢁ
ꢁ
a) Telescoped preparation of α-aminotrifluoroborates from boronic acids
Condition A: α-aminotrifluoroborate with dimethylamine
1. Pd(PPh3)2Cl2, Cu(OAc)2,
Na2CO3, TFE, 50 °C, 16 h
Me
N
Me
Me
Me
Ar
N
H
Ar B(OH)2
2. KBH4, CH3CN/CH3OH (4:1)
0 °C to rt, 4 h
EtS
BF3
BF3
R
or EtMgBr, THF, –78 °C, 4 h
1
Condition B: α-aminotrifluoroborate with other amines
1. Pd(PPh3)2Cl2, Cu(OAc)2, Na2CO3
ꢈꢁꢉꢊꢋꢌꢍꢃꢎꢏꢃꢄꢃꢊꢐꢑꢅ
TFE/H2O (9:1), 50 °C, 16 h
2. amine, AcOH, CH3CN, rt, 1 h
Me
Me
N
N
R
H
Ar B(OH)2
ꢓ48,8.4,6ꢁ =?::9<>ꢁ A,=ꢁ :<9@4/0/ꢁ -Cꢁ ꢔ64ꢁ ꢕ466Cꢁ >3<9?23ꢁ >30ꢁ ꢕ466Cꢁ
$0=0,<.3ꢁ ꢀA,</ꢁ #<92<,7ꢁ ꢊꢕ$ꢀ#ꢋꢃꢁ ꢀꢃꢁ %ꢃꢁ ,.589A60/20=ꢁ >30ꢁ
%.396,<=34:ꢁ ꢓ?8/ꢁ 91ꢁ >30ꢁ %A4==ꢁ ꢆ3074.,6ꢁ ꢄ8/?=><Cꢁ ꢊ%%ꢆꢄꢋꢁ 19<ꢁ ,ꢁ
10669A=34:ꢃꢁ'0ꢁ>3,85ꢁ>30ꢁꢕ"ꢆꢁ! $ꢁ=0<@4.0ꢁ,8/ꢁ>30ꢁ 960.?6,<ꢁ,8/ꢁ
ꢏ497960.?6,<ꢁꢀ8,6C>4.,6ꢁ%0<@4.0=ꢁꢊ 9ꢏ4ꢀ%ꢋꢁ19<ꢁ,8,6C=0=ꢃꢁ
3. KBH4, CH3CN/CH3OH (4:1)
0 °C to rt, 4 h
EtS
BF3
Ar
BF3
or EtMgBr, THF, –78 °C, 4 h
1
Me
Me
Me
Me
N
H
N
N
H
H
O
O
BF3
BF3
BF3
S
Et
5a, 83%a
ꢒꢃꢓꢌꢋꢔꢎꢑꢕꢁ,.C6-9<98ꢁ.97:9?8/=ꢁFꢁ.<9==ꢅ.9?:6482ꢁFꢁ-9<984.ꢁ
F
5b, 92%a
5c, 89%b
,.4/=ꢁFꢁ=C8>30>4.ꢁ70>39/=ꢁFꢁDA4>>0<498=ꢁ
O
N
H
N
H
tBu
BF3
* +ꢁꢁ ꢐꢃꢁꢀꢃꢁ 96,8/0<ꢂꢁꢉꢃꢁ$,?=306ꢂꢁ!ꢃꢁ ꢃꢁꢔ664=ꢂꢁꢉꢃꢁ"<2ꢃꢁꢆ307ꢃꢁꢇꢈ ꢈꢂꢁꢖꢗꢂꢁꢒꢍꢈꢒH
ꢒꢍꢈꢌꢃꢁ
BF3
Et
NC
*ꢇ+ꢁꢁ ,ꢋꢁꢀꢃꢁ ꢃꢁꢘ?7,=ꢂꢁꢐꢃꢁꢀꢃꢁ 96,8/0<ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢊꢍ"%ꢉꢊꢎꢏꢉꢁ
ꢖꢗꢘꢖꢂꢁꢐꢑꢂꢁꢗꢌꢙꢍHꢗꢌꢙꢌꢎꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢁꢖꢗꢘꢖꢂꢁꢑꢒ ꢂꢁꢗꢖꢙ Hꢗꢖꢙꢒꢎꢁ-ꢋꢁꢚꢃꢁ!9/,ꢂꢁ
ꢐꢃꢁꢔ<J=ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢓꢉꢊꢆ!ꢉꢊꢋꢌꢈ!ꢉꢊꢔ#ꢕꢉꢁꢖꢗꢘꢆꢂꢁꢑꢖꢗꢂꢁꢗꢌ Hꢗꢌ ꢒꢃꢁ
*ꢍ+ꢁꢁ ꢀꢃꢁ"=?8,ꢁꢐE6@0Dꢂꢁꢆꢃꢁ#ꢃꢁ%.3,,.5ꢂꢁꢚꢃꢁ!9/,ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢓꢉꢊꢆ!ꢉꢊꢋꢌꢈ!ꢉꢊ
ꢔ#ꢕꢉꢁꢖꢗꢘꢙꢂꢁꢑꢖꢘꢂꢁ ꢙꢇꢌH ꢙꢇꢛꢃꢁ
5d, 79%b
5e, 82%b
b) Synthesis of α-aminoboronic acids and amines from α-aminotrifluoroborates4
• HCl
N
N
SiCl4
H
*ꢒ+ꢁꢁ &ꢃꢁ%34<9ꢂꢁꢀꢃꢁ%.3?37,.30<ꢂꢁ ꢃꢁꢑꢃꢁꢉ,.56ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢋꢌꢈ!ꢉꢊꢔꢕꢅꢉꢁꢖꢗꢘ ꢂꢁꢘꢂꢁ
ꢗ ꢛ Hꢗ ꢛꢌꢃꢁ
ref. 4
BF3
B(OH)2
*ꢗ+ꢁꢁ ꢆꢃꢁꢉꢃꢁ'34>0ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢆꢋꢔꢊꢋꢈ"%ꢉꢊꢔꢕꢅꢉꢁꢖꢗꢘ ꢂꢁ ꢂꢁ ꢛꢖHꢇꢈꢌꢃꢁ
*ꢌ+ꢁꢁ ,ꢋꢁꢐꢃꢁ!ꢃꢁꢏ9<9==ꢂꢁꢘꢃꢁ%.3,?08-?<2ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢙꢈ 'ꢉꢊꢋꢌꢅ!ꢉꢊꢆꢕ%ꢁꢁꢖꢗꢘꢚꢂꢁ
ꢑꢚꢒꢂꢁ0 ꢙꢈꢈꢇ ꢒꢎꢁ-ꢋꢁꢀꢃꢁꢆ349>0664=ꢂꢁꢚꢃꢁꢀ370/ꢂꢁ&ꢃꢁꢏ0>D06ꢂꢁ ꢃꢁ&,8<4@0<ꢂꢁꢆꢃꢁꢉꢃꢁ
'34>0ꢂꢁ %ꢃꢁ ꢘ,ꢁ $9=ꢂꢁ $ꢃꢁ %.34-64ꢂꢁ ꢉꢃꢁ 'ꢃꢁ ꢏ9/0ꢂꢁ %ꢃꢁ ꢃꢁ ꢀ70>,70Cꢂꢁ ꢋꢌꢈ!ꢉꢊ
ꢋ#!!&"ꢉꢁꢖꢗꢖꢗꢂꢁꢐꢗꢂꢁꢖꢇꢍHꢖꢇꢌꢃꢁ
F
F
5c
α-aminoboronic acid
Zr(OiPr)4
N
N
H
*ꢖ+ꢁꢁ ,ꢋꢁ ꢘꢃꢁ ,D?848ꢂꢁ !ꢃꢁ ꢏ<92?40<0ꢂꢁ ꢃꢁ )089-4ꢅ'982ꢂꢁ ꢉꢃꢁ 'ꢃꢁ ꢏ9/0ꢂꢁ ꢆꢋꢔꢊ
ꢛꢅ#!ꢁ%ꢈ$ꢉꢊꢔꢕꢅꢉꢊꢎ"ꢇꢉꢁꢖꢗꢘꢛꢂꢁꢑꢂꢁꢒꢗꢌHꢒꢌꢇꢎꢁ-ꢋꢁꢘꢃꢁ ,D?848ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢙꢈ 'ꢉꢊ
ꢋꢌꢅ!ꢉꢊꢆꢕ%ꢁꢁꢖꢗꢘꢙꢂꢁꢑꢚꢚꢂꢁ0 ꢌꢈꢈꢍ ꢎꢁ.ꢋꢁꢘꢃꢁ%.3,?08-?<2ꢂꢁꢀꢃꢁ"=?8,ꢁꢐE6@0Dꢂꢁ
ꢉꢃꢁ 'ꢃꢁ ꢏ9/0ꢂꢁ ꢓꢉꢊ ꢜꢁ%ꢈ$ꢉꢊ ꢋꢌꢈ!ꢉꢊ ꢛꢁ ꢖꢗꢘ ꢂꢁ ꢗꢂꢁ ꢒꢖꢖꢗHꢒꢖꢙꢇꢎꢁ /ꢋꢁ (ꢃꢁ ꢐ?ꢂꢁ ꢘꢃꢁ
%.3,?08-?<2ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢉꢃꢁꢀꢃꢁꢉ938=98ꢂꢁꢓꢉꢊꢆ!ꢉꢊꢋꢌꢈ!ꢉꢊꢔ#ꢕꢉꢁꢖꢗꢘ ꢂꢁꢑ ꢚꢂꢁ
ꢒꢈꢍꢍH ꢒꢈꢍꢖꢎꢁ 0ꢋꢁ ꢘꢃꢁ %.3,?08-?<2ꢂꢁ ꢃꢁ ꢘ4@,8/,<4ꢂꢁ ꢑꢃꢁ !0?7,88ꢂꢁ ꢆꢃꢁ ꢀꢃꢁ
%:40206ꢂꢁ&ꢃꢁꢚ,.50>>ꢂꢁ(ꢃꢁꢘD082ꢂꢁ!ꢃꢁꢘꢃꢁ%:08.0<ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢊ
ꢍ"%ꢉꢊꢎꢏꢉꢁꢖꢗꢖꢗꢂꢁꢑꢑꢂꢁꢖꢌꢈꢛHꢖꢌ ꢒꢎꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢁꢖꢗꢖꢗꢂꢁꢑꢖꢒꢂꢁ ꢒꢖꢌꢒH ꢒꢖꢖ ꢃꢁ
*ꢙ+ꢁꢁ ,ꢋꢁꢐꢃꢁꢔ<J=ꢂꢁ(ꢃꢁꢑ?=34/,ꢂꢁꢉꢃꢁ'ꢃꢁꢏ9/0ꢂꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢊꢍ"%ꢉꢊꢎꢏꢉꢁꢖꢗꢘꢆꢂꢁꢐꢖꢂꢁ
ꢖꢌꢈꢒHꢖꢌꢈꢖꢎꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢁꢖꢗꢘꢆꢂꢁꢑꢒꢗꢂꢁꢖꢖꢍꢒHꢖꢖꢍꢖꢎꢁ-ꢋꢁꢘꢃꢁ'?ꢂꢁ!ꢃꢁꢀꢃꢁꢓ938ꢁ
ꢉꢃꢁ 'ꢃꢁ ꢏ9/0ꢂꢁ ꢆ"ꢇꢈ(ꢉꢊ ꢋꢌꢈ!ꢉꢊ ꢍ"%ꢉꢊ ꢎꢏꢉꢁ ꢖꢗꢘꢚꢂꢁ ꢐꢝꢂꢁ ꢈꢗꢙH ꢈꢌꢇꢎꢁ ꢆ"ꢇꢈ(ꢉꢊ
ref. 4
BF3
H
Et
Et
NC
NC
5e
amine
ꢁ
ꢀꢁꢂꢃꢄꢃꢅ ꢆꢇꢁ &060=.9:0/ꢁ 19<7,>498ꢁ 91ꢁ αꢅ,7489><416?9<9-9<,>0=ꢁ ,1>0<ꢁ .<9==ꢅ
.9?:6482ꢃꢁ &30ꢁ αꢅ,7489><416?9<9-9<,>0=ꢁ .,8ꢁ -0ꢁ .98@0<>0/ꢁ 48>9ꢁ αꢅ,7489-9<984.ꢁ
,.4/=ꢁ 9<ꢁ ,7480=ꢃꢁ &30ꢁ C406/=ꢁ ,<0ꢁ 4=96,>0/ꢁ C406/=ꢃꢁ $0,.>498=ꢁ :0<19<70/ꢁ 98ꢁ
ꢈꢃꢇꢁ7796ꢁ=.,60ꢃꢁꢁαꢅ,7489><416?9<9-9<,>0ꢁA4>3ꢁꢀꢂꢀꢃ/470>3C6,7480ꢁ:<0:,<0/ꢁA4>3ꢁ
.98/4>498=ꢁ ꢀꢎꢁ ꢄαꢅ,7489><416?9<9-9<,>0ꢁ A4>3ꢁ 9>30<ꢁ ,7480=ꢁ :<0:,<0/ꢁ A4>3ꢁ
.98/4>498=ꢁꢏꢃꢁ
ꢋꢌꢈ!ꢉꢁꢖꢗꢘꢚꢂꢁꢑꢖꢑꢂꢁ
ꢖꢒH
ꢖꢙꢃꢁ
*ꢛ+ꢁꢁ ꢕꢃꢁꢆ3082ꢂꢁ%ꢃꢁ)3,9ꢂꢁ!ꢃꢁ#ꢃꢁ ,85,/ꢂꢁꢆ"ꢇꢈ(ꢉꢊꢋꢌꢈ!ꢉꢊꢍ"%ꢉꢊꢎꢏꢉꢁꢖꢗꢖꢗꢂꢁꢘ"ꢄꢜꢁ
ꢈꢃ ꢈꢈꢇꢝ,840ꢃꢇꢈꢇꢈ ꢇꢍꢖꢍꢃꢁ
4
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