are prepared by reducing the triple bond to a double bond in a compound II wherein R 16 represents # OH, # OH or - - - OH or the optically active antipode thereof with an alkali metal aluminium hydride, if desired introducing the protecting group R 1 , if desired also introducing the...
Next, the Smiles rearrangement process takes place, generating an N-center radical intermediate B simultaneously forming a new C–C bond with the alkynyl-linked phenyl ring and expelling SO2. Subsequently, the electrophilic N-amidyl radical undergoes addition procedure to the triple bond to form a ...
Here we construct a one-pot concurrent chemoenzymatic cascade by integrating organobismuth-catalyzed aldol condensation with ene-reductase (ER)-catalyzed enantioselective reduction, enabling the formal asymmetric α-benzylation of cyclic ketones. To achieve this, we develop a pair of enantiocomplementary ...
The phosphino-containing complex 1a has the ability to promote the addition of hydrogen to a triple bond in a trans-selective manner, affording E-stilbene (E-3a) with up to 99:1 E/Z selectivity (Fig. 2c). By contrast, complex 1b that contains an imino anchor in a CAAC ligand allows...
Reflecting such weakening, this central bond of the compound 15 was readily cleaved by potassium metal to give a new cyclohexane having two BCO-annelated cyclopentadienide ion 4 (ref. 5). The bond cleavage also takes place thermally to give the isomeric hydrocarbon, which is tentatively assigned...
16 The erythromycin A was used as a model compound to demonstrate novel MAS NMR techniques. The homonuclear correlation method17 provides a means to assign 13C isotropic chemical shifts via recoupling of the homonuclear dipolar interaction under fast MAS. The magic-angle turning method18 enables ...
For 1–5, the geometries of the double bond Δ2, 3 for 1–2 and Δ2, 3 and Δ4, 5 for 3 − 5 were assigned as E configuration on the basis of the Figure 3 Key NOESY correlations for compound 1. A full color version of this figure is available at The Journal of Antibiotics...
(so-called compound I) have been investigated thoroughly for C-H bond oxyfunctionalization reactions12,16. P450s are typically dependent on nicotinamide cofactors (NADP(H)) coupled with a regeneration system to reduce O2as the oxygen source, and the resultant sophisticated electron transport chains ...
tin compound, titanium compound, transition metal salt, a salt of the acid corresponding to the ester and the like; Reaction 6) the free radical addition of a thioacid across a carbon-carbon double bond of an alkene-functional silane, catalyzed by UV light, heat, or the appropriate free ra...
In an aspect, there is provided a compound of formula (I):whereinR1 is H; lower alkyl; aryl; heteroaryl; alkenyl; or heterocycle; all of which are optionally substituted at one or more substitutable positions with one or more suitable substituents;...