Lewis base-catalyzed divergent isomerizations of 5-hydroxyl-2,3-dienoate
作者:Wei Dong、Pengfei Hu、Jian Hu、Xiaofeng Tong
DOI:10.1016/j.tetlet.2013.10.059
日期:2014.3
A divergent isomerization of 5-hydroxyl-2,3-dienoate 1 catalyzed by Lewis base has been developed, the phosphine catalyst leads to 5-oxohex-2(3)-enoates 2 while DABCO catalyst affords 3-ethoxy α,β-unsaturated lactone 3.
This invention relates to methods of using compositions having health enhancing qualities, and more particularly to compositions having kavalactones, as well as use and preparation of the compositions.
This invention relates to compositions having health enhancing qualities, and more particularly to compositions having kavalactones, as well as use and preparation of the compositions.
A wood preservative that comprises as an active ingredient a Piper methysticum, plant or a processed product thereof or a compound represented by Formula (I):
1
wherein R
1
, R
2
, R
3
, R
4
and R
16
are same or different and each denotes a hydrogen atom, hydroxy or a C
1-4
alkoxy, or R
1
and R
2
are taken together to form a group represented by —O—(CH
2
)
n
—O— wherein n is an integer of 1 to 3, R
5
is a C
1-4
alkoxy and X is —CH=CH—, —CH
2
—CH
2
— or epoxyethylene, and the bond:
denotes a single bond or a double bond can prevent the attacking wood by an insect harmful to the wood and also prevents the appearance and the growth of a wood-rotting fungus or a wood- staining fungus while being highly safe to humans and animals without exerting no adverse effect on the environment.
Efficient Enantioselective Hetero-Diels−Alder Reaction of Brassard's Diene with Aliphatic Aldehydes: A One-Step Synthesis of (<i>R</i>)-(+)-Kavain and (<i>S</i>)-(+)-Dihydrokavain
An efficient catalytic asymmetrichetero-Diels-Alderreaction of Brassard'sdiene with aliphatic aldehydes was reported. The catalyst, which was generated from (R)-BINOL, Ti(i-PrO)4, and 4-picolyl chloride hydrochloride, promoted the reaction smoothly to afford the corresponding alpha,beta-unsaturated delta-lactone derivatives in moderate-to-good yields (46-79%) with high enantioselectivities (up to