Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• substituted indoles 1–4. Using a solid-phase screen as before, the level of colour formation in colonies was assessed visually, generating ‘fingerprints’ of activity as summarised in Figure 2 (also see Figure S1, Supporting Information File 1). The fingerprints show that variations in the configuration of the

• (R,S)-12 alcohols (37%) albeit with a slight decrease in selectivity (15%). Conclusion A colony-based solid-phase screen for P450 indole activity was developed and used to generate a population of 93 indole active enzyme variants from screening a large library (16,500) of variants. The application of

Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• : perfluorinated solvents; phase screen; PTFE; semipermeable membrane; synthesis design; Introduction Fluorous reactions are a relatively new addition to the portfolio of synthetic methods [1][2][3][4][5]. In a fluorous triphasic reaction, introduced by Curran in 2001, a fluorous phase screen was used to

• (polytetrafluoroethylene, Teflon) tape as a phase screen [21][22][23]. In a PTFE tape phase-vanishing reaction (PV-PTFE), a delivery tube containing the reagent is sealed on both ends with PTFE tape. The PTFE tape covering the top of the delivery tube prevents the loss of the reagent over the course of the reaction. The

Solvent-free phase-vanishing reactions with PTFE (Teflon^®) as a phase screen

• Kevin Pels and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2009, 5, No. 75, doi:10.3762/bjoc.5.75

• Kevin Pels Veljko Dragojlovic Wilkes Honors College of Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA 10.3762/bjoc.5.75 Abstract In a solvent-free phase-vanishing reaction with PTFE (polytetrafluoroethylene, Teflon®) tape as the phase screen, a thermometer adapter is

• perfluoroalkane acts as a phase screen to separate the two reactants, one of which is more dense than the screen and the other one that is less dense. If both reactants are less dense than the phase screen, one can carry out the reaction in a U-tube and if both reactants are denser than the screen, the reaction

• can be carried out in an inverted U-tube. As the reagent diffuses through the perfluoroalkane, it reaches the substrate and reacts with it. In the course of the reaction, the reagent is used up (“vanishes”). One disadvantage of PV reactions is that a commonly used phase screen, fluorinert liquid FC-72

Phase- vanishing halolactonization of neat substrates

• Nicole Windmon and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2008, 4, No. 29, doi:10.3762/bjoc.4.29

• triphasic reactions which involve a reagent, a liquid perfluoroalkane as a phase screen and a substrate. The perfluoroalkane does not dissolve any of the reactants and is used to separate them. Halolactonization of neat substrates under phase-vanishing conditions avoids use of both solvents and basic

• -vanishing brominations is addition of water as the fourth phase to act as an acid scavenger [4]. The perfluoroalkane does not dissolve the reactants and is used as a phase screen to separate them. In this procedure, the halogen reagent is of a higher density while the substrate is of a lower density than

• the perfluoroalkane phase screen. As the reagent in the lower layer diffuses through the perfluoroalkane layer, it reaches the top layer and reacts with it. Since the rate of diffusion is relatively low, the reaction proceeds at a moderate rate, instead of a vigorous, often violent, reaction that