Triphenylphosphine → 2-tert-Butoxycarbonylamino-2-(2-oxo-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoic acid ethyl ester

HRID 579491Notes

Reaction equation

HRID 579491 reaction equation
[CH2:1]([O:3][C:4](=[O:30])[C:5]([CH2:27][CH:28]=C)([NH:19][C:20]([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21])[CH2:6][CH2:7][CH2:8][CH2:9][B:10]1[O:14][C:13]([CH3:16])([CH3:15])[C:12]([CH3:18])([CH3:17])[O:11]1)[CH3:2].[O:31]=[O+][O-].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>ClCCl>[CH2:1]([O:3][C:4](=[O:30])[C:5]([NH:19][C:20]([O:22][C:23]([CH3:25])([CH3:26])[CH3:24])=[O:21])([CH2:27][CH:28]=[O:31])[CH2:6][CH2:7][CH2:8][CH2:9][B:10]1[O:11][C:12]([CH3:17])([CH3:18])[C:13]([CH3:15])([CH3:16])[O:14]1)[CH3:2]

Participants

5

Reactant 3

HCID 11776TriphenylphosphineHCID 24823Ozone2×HCID 66833330Ethyl-2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

Product 1

HCID 866637142-tert-Butoxycarbonylamino-2-(2-oxo-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoic acid ethyl esterYield 93%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of Ethyl-2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate (650 mg, 1.53 mmol) in dichloromethane (30 mL,) was cooled to −78° C. and treated with ozone until a pale blue-gray color appeared. After TLC indicated the absence of starting material, the ozone inlet tube was replaced with nitrogen and nitrogen was bubbled through the solution for 20 min to remove any excess ozone. Triphenylphosphine (1.20 g, 4.59 mmol, 3 equiv) was added in one portion, the cooling bath was removed and the mixture was stirred for 4 h. The solution was concentrated and purified by MPLC (0-40% ethyl acetate in heptane) gave the title compound as a colorless oil (608 mg, 93%). Rf 0.25 (30% ethyl acetate in heptane); 1H NMR (CDCl3, 300 MHz): δ 9.64 (s, CHO, 1H), 5.60 (br, s, NH, 1H), 4.19 (q, J=7.5 Hz, 2H), 3.56 (d, J=17 Hz, 1H), 2.93 (d, J=17.5 Hz, 1H), 2.20 (m, 1H), 1.62 (m, 1H), 1.38 (s, 9H), 1.28-1.43 (m, 4H), 1.23 (t, J=7 Hz, 3H), 1.21 (s, 12H) and 0.72 (t, J=7.5 Hz, 2H).

Workup

  1. customwas bubbled through the solution for 20 min
  2. customto remove any excess ozone
  3. customthe cooling bath was removed
  4. concentrationThe solution was concentrated
  5. custompurified by MPLC (0-40% ethyl acetate in heptane)

Sources & evidence

ORD record
ord-b5288f0940934535aae1006d802ef89d
Source dataset
uspto-grants-2015_05
Patent number
US09040703B2

Reaction notes

Loading…