Metallic samarium and iodine promoted facile and efficient syntheses of trisubstituted alkenes from the acetates of Baylis–Hillman adducts

Total synthesis of (+)-grandiamide D, dasyclamide and gigantamide A from a Baylis-Hillman adduct: A unified biomimetic approach

A unified strategy was followed for the synthesis of three putrescine bisamides, (+)-grandiamide D, dasyclamide and gigantamide A, isolated from leaves of Aglaia gigantea, by making use of a common synthetic intermediate prepared by the Baylis–Hillman reaction. Asymmetric synthesis of the natural (+)-grandiamide D was accomplished from camphor sultam.

Regio- and Stereoselective Synthesis of α,β-dehydro-β-amino Esters

A facile method for the regio- and stereoselective synthesis of α,β-dehydro-β-amino esters from acetates of Baylis-Hillman adducts with amines was reported. In the absence of any solvent and catalyst, the present strategy works well for a series of electron deficient and electron rich aromatic amines as well as aliphatic ones.

Application of the 4-trifluoromethylbenzenepropargyl ether group as an unhindered, electron deficient protecting group for stereoselective glycosylation

4-Trifluoromethylbenzenepropargyl ethers are stable and sterically minimal alcohol protecting groups that are readily cleaved in a single step by exposure to lithium naphthalenide. In conjunction with the 4,6-O-benzylidene protecting group, glycosylation reactions of 2-O-(4-trifluoromethylbenzenepropargyl)-protected mannosyl donors are extremely beta-selective.

Syntheses of (Z)-Allyl Chlorides from Baylis–Hillman Adducts with a Trichlorotriazine/DMF System

Stereoselective transformation of Baylis–Hillman adducts 1 into corresponding ( Z)-allyl chlorides 2 have been achieved by treatment with 2,4,6-trichloro [1,3,5]triazine and N, N-dimethyl formamide. This novel approach proceeds readily at room temperature within a few hours with excellent yields and stereoselectivity.

Remarkable rate acceleration of SmI3-mediated iodination of acetates of Baylis-Hillman adducts in ionic liquid: facile synthesis of (Z)-allyl iodides

Stereoselective transformation of Baylis-Hillman acetates 1 into corresponding (Z)-allyl iodides 2 has been achieved by treatment of 1 with samarium triiodide in THF. Remarkable rate acceleration of samarium triiodide-mediated iodination of 1 was found when ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluroborate ([bmim]BF(4)) was used as reaction media in stead of THF. This novel approach proceeds readily at 50 degrees C within a few minutes to afford (Z)-allyl iodides 2 in excellent yields. A mechanism involving stereoselective iodination of the acetates of Baylis-Hillman adducts by samarium triiodide is described, in which a six-membered ring transition state played a key role in the stereoselective formation of 2.