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Competing often with these petroleum-derived products are derivatives of fatty acids, such as fatty alcohols and fatty amines. [2] Low molecular weight alpha-olefins (butenes, hexenes, etc.) are used as comonomers, which are incorporated into polyethylene. Some are subjected to olefin metathesis as a route to propylene.
Reduction of alkynes is a useful method for the stereoselective synthesis of disubstituted alkenes. If the cis -alkene is desired, hydrogenation in the presence of Lindlar's catalyst (a heterogeneous catalyst that consists of palladium deposited on calcium carbonate and treated with various forms of lead) is commonly used, though hydroboration ...
In the example shown below, the para-methoxybenzoyl substituent serves primarily as a source of steric bulk to allow the catalyst to differentiate the two faces of the alkene. [23] SAD scheme 3. It is often difficult to obtain high diastereoselectivity on cis-disubstituted alkenes when both ends of the olefin have similar steric environments.
Hydroboration of 1,2-disubstituted alkenes, such as a cis or trans olefin, produces generally a mixture of the two organoboranes of comparable amounts, even if the steric properties of the substituents are very different. For such 1,2-disubstituted olefins, regioselectivity can be observed only when one of the two substituents is a phenyl ring.
Many higher alcohols are produced by hydroformylation of alkenes followed by hydrogenation. When applied to a terminal alkene, as is common, one typically obtains a linear alcohol: [25] RCH=CH 2 + H 2 + CO → RCH 2 CH 2 CHO RCH 2 CH 2 CHO + 3 H 2 → RCH 2 CH 2 CH 2 OH. Such processes give fatty alcohols, which are useful for detergents.
Straight-chain terminal alkenes, also called linear alpha olefins (LAO) or normal alpha olefins (NAO), are alkenes (olefins) having a chemical formula C n H 2n, distinguished from other alkenes with a similar molecular formula by being terminal alkenes, in which the double bond occurs at the alpha (α-, 1-or primary) position, and by having a linear (unbranched) hydrocarbon chain.
One of the key steps in the strategy used for the synthesis of the C3-C16 fragment was a chirally catalyzed ene reaction that installed the C15 stereocenter. Treatment of the terminal allyl group of compound 1 with ethyl glyoxylate in the presence of catalytic (S)-BINOL-TiBr 2 provided the required alcohol in 74% yield and >95% ds. This method ...
Due to the rearrangement of the double bond, terminal olefins tend to give primary allylic alcohols: Cyclic alkenes prefer to undergo allylic oxidation within the ring, rather than the allylic position at the sidechain. In bridged ring systems, Bredt’s rule is followed and bridgehead positions are not oxidized: