Part 3. Triethylborane- air: a suitable initiator for intermolecular radical additions of S-2-oxoalkyl- thionocarbonates (S-xanthates) to olefins

• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 47, doi:10.1186/1860-5397-3-47

• S-alkyl-thionocarbonates (S-xanthates), O-alkyl-thionocarbonates (O-xanthates) and related compounds to the corresponding alkanes at room temperature.[7] In the present article, we wish to report that a more comprehensive understanding of the different routes involved permits the premature reduction

Part 2. Mechanistic aspects of the reduction of S-alkyl- thionocarbonates in the presence of triethylborane and air

• Florent Allais,
• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 46, doi:10.1186/1860-5397-3-46

• corresponding alkanes with good to excellent yields. Such a process complies with the long-standing pursuit of an environmentally acceptable process for desulfurisation, dehalogenation or deoxygenation that operates under mild reaction conditions. In this context, special attention must be paid to a paper

• plurality of mechanisms.[3] The reactivity of the combination alkylborane/air/water touches many other domains and certainly deserves further study. Xanthates 1a, 2a and their corresponding alkanes. Deuterated O-ethyl-S-ethyl dithiocarbonates 3–5, deuterated adduct 1d and alkane 1e. Kinetics of the

Part 1. Reduction of S-alkyl- thionocarbonates and related compounds in the presence of trialkylboranes/air

• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 45, doi:10.1186/1860-5397-3-45

• -dithiocarbonates (S-xanthates), iodides, O-alkyl-dithiocarbonates (O-xanthates) and related compounds to the corresponding alkanes is very important in organic synthesis, especially in natural products chemistry.[1][2] Deoxygenation (Barton-McCombie reaction) has been largely used to handle sensitive compounds

• and 2b, respectively. Interestingly, secondary S-alkylxanthates 3a–5a were cleanly reduced to the corresponding alkanes in excellent yields (up to 80%) (Table 1, entries 3–5). When the starting material was soluble enough, there was no need for an extra solvent other than the mixture of hexanes

• . Thus, compounds 10a, 12a–14a gave the corresponding alkanes in fair to good yields (entries 8–11). The reduction of a tertiary xanthate, without risk of any pseudo-Tchugaev thermal elimination, was also feasible in good yield as shown by reaction of compound 15a (entry 12). Attempts to reduce a primary

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

• David O'Hagan,
• Henry S. Rzepa,
• Martin Schüler and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2006, 2, No. 19, doi:10.1186/1860-5397-2-19

• Jt = 32 Hz are estimated values. The observed 3JHF coupling constants are an average over the rotational isomers. Synthesis of vicinal dimethyl difluorosuccinates. The conversion of the tartrates 1 with SF4 and HF [6][7]. Schlosser's route to vicinal erythro- or threo- difluoro alkanes 5 [13