189701-49-3

Upstream product

• 2014-83-7 1,3-Dichloro-2-chloromethyl-benzene 
• 1707-77-3 1,2:5,6-di-O-isopropylidene-D-mannitol 

Downstream Products

• 170874-85-8 (5S,1'S,2'R)-4-<1-(2,6-Dichlorobenzyloxy)-2,3-dihydroxypropyl>-5-(hydroxymethyl)furan-2-(5H)-one 
• 170874-83-6 (R)-2-(2,6-Dichloro-benzyloxy)-1,2-bis-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl)-ethanone 

Relevant academic research and scientific papers

Diastereoselective Grignard Additions to O-Protected Polyhydroxylated Ketones: A Reaction Controlled by Groundstate Conformation?

The O-protected polyhydroxy ketones 9-14 and 39, 42 add σ-type Grignard reagents with >90:10 stereoselectivity to give the 3,4-syn-adducts 17-22 and 43, 45, respectively, as the major diastereomers (Tables 1 and 2). The stereoselectivity is interpreted in terms of early transition states which are very close to the groundstate conformations shown in Figure 6 and 7. These demonstrate that the "top face" of the carbonyl group is much less shielded than the "bottom" face, Complexation phenomena are of minor importance. It is also shown that the classical transition state models (Felkin-Anh or chelate Cram) are not applicable to polyoxygenated ketones.

New Chiral Building Blocks from 1,2;5,6-Di-O-isopropylidene-D-mannitol: Synthesis of C2-Symmetrical and Unsymmetrical Mono- and Bisepoxides and of a Polyhydroxylated Butenolide

The enantiopure epoxides 2-6 were synthesized from 1,2;5,6-di-O-isopropylidene-D-mannitol (1).The terminal epoxides 2 and 3 are available from the desoxy mannitol 9 in three steps.The C2-symmetrical epoxides 4 and 5 were generated via the C-4-inverted alcohol 15.The C2-symmetrical bisepoxide 6 was prepared in a short sequence maintaining the symmetry throughout the entire synthesis.The crystalline butenolide 44 was prepared in five steps from 1 by Wittig olefination and lactonization. - Key Words: Epoxides, C2-symmetrical / Bisepoxides / Butenolide, polyhydroxylated