Abstract
Original language | English |
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Pages (from-to) | 5424-5427 |
Number of pages | 4 |
Journal | Organic Letters |
Volume | 15 |
Issue number | 21 |
Early online date | 15 Oct 2013 |
DOIs | |
Publication status | Published - 1 Nov 2013 |
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Asymmetric Lithiation Trapping of N-Boc Heterocycles at Temperatures above −78 °C. / Gelardi, Giacomo; Barker, Graeme; O'Brien, Peter; Blakemore, David C.
In: Organic Letters, Vol. 15, No. 21, 01.11.2013, p. 5424-5427.Research output: Contribution to journal › Article
TY - JOUR
T1 - Asymmetric Lithiation Trapping of N-Boc Heterocycles at Temperatures above −78 °C
AU - Gelardi, Giacomo
AU - Barker, Graeme
AU - O'Brien, Peter
AU - Blakemore, David C.
PY - 2013/11/1
Y1 - 2013/11/1
N2 - The asymmetric lithiation trapping of N-Boc heterocycles using s-BuLi/chiral diamines at temperatures up to −20 °C is reported. Depending on the N-Boc heterocycle, lithiation is accomplished using s-BuLi and (−)-sparteine or the (+)-sparteine surrogate in the temperature range −50 to −20 °C for short reaction times (2–20 min). Subsequent electrophilic trapping or transmetalation–Negishi coupling delivered functionalized N-Boc heterocycles in 47–95% yield and 77:23–93:7 er. With N-Boc pyrrolidine, trapped products can be generated in ∼90:10 er even at −20 °C.
AB - The asymmetric lithiation trapping of N-Boc heterocycles using s-BuLi/chiral diamines at temperatures up to −20 °C is reported. Depending on the N-Boc heterocycle, lithiation is accomplished using s-BuLi and (−)-sparteine or the (+)-sparteine surrogate in the temperature range −50 to −20 °C for short reaction times (2–20 min). Subsequent electrophilic trapping or transmetalation–Negishi coupling delivered functionalized N-Boc heterocycles in 47–95% yield and 77:23–93:7 er. With N-Boc pyrrolidine, trapped products can be generated in ∼90:10 er even at −20 °C.
U2 - 10.1021/ol402395j
DO - 10.1021/ol402395j
M3 - Article
VL - 15
SP - 5424
EP - 5427
JO - Organic Letters
JF - Organic Letters
SN - 1523-7060
IS - 21
ER -