138124-12-6Relevant academic research and scientific papers
Comparative Studies on the Synthesis of an anti,syn Stereotriad with Chiral Allenylstannane and Allenylindium Reagents
Marshall, James A.,Palovich, Michael R.
, p. 6001 - 6005 (1997)
Addition of the chloroallenylstannane derived from the Bu3Sn allene (S)-2 and SnCl4 to nonracemic α-methyl-β-oxygenated aldehyde 1a afforded mixtures of anti,syn and anti,anti adducts 3a and 3b. When InCl3 was employed in the transmetalation of allenylstannane (S)-2, a mixture of adducts 3a and ent-3b was produced. Experiments with the β-ODPS aldehydes 1b and 5 showed that InBr3 and InI3 yield a transient InXn species from allenylstannane (S)-2 with mainly retention of configuration. In contrast, transmetalation of (S)-2 with SnCl4 or BuSnCl3 affords an intermediate allenyl species of inverted configuration. The (S)-2/BuSnCl3 reagent showed high enantio- and diastereoselectivity in addition to aldehydes 1a, 1b, and 5. The (S)-2/InBr3 or InI3 reagent, while somewhat less selective, afforded enantiomeric or diastereomeric adducts.
Synthesis of syn,syn; anti,syn; syn,anti; and anti,anti Stereotriads from a Single Pair of Enantiomeric Reagents
Marshall, James A.,Perkins, Jolyon F.,Wolf, Mark A.
, p. 5556 - 5559 (1995)
The stannanes (S)-1a, (R)-1b, and (S)-1c add to (S)- and (R)-2-methyl-3-(benzyloxy)propanal ((S)-2 and (R)-2) to afford the syn,syn (BF3*OEt2 promotion), syn,anti (MgBr2*OEt2 promotion), anti,anti (SnCl4-derived reagent in CH2Cl2), and anti,syn (SnCl4-derived reagent in hexane) stereotriad adducts 3, 4, 6, and 7.
Synthesis of Enantioenriched Homopropargylic Alcohols through Diastereoselective SE' Additions of Chiral Allenylstannanes to Aldehydes
Marshall, James A.,Wang, Xiao-jun
, p. 1242 - 1252 (2007/10/02)
Allenylstannanes (S)-4 and (R)-4, available in ca. 90percent ee from alkynones 1 through reduction with the LiAlH4-Darvon alcohol or -ent-Darvon alcohol complex, followed by SN2' displacement on the derived mesylates (R)-3 or (S)-3 with Bu3SnLi*CuBr*Me2S, readily add to various aldehydes under Lewis acid catalysis to afford optically active homopropargylic alcohols with good to excellent syn diastereoselectivity.With 2-(benzyloxy)propanal (48), MgBr2-catalyzed reactions are highly stereoselective, affording the syn adduct 49 from the (S)-stannane (S)-4 and the anti adduct 52 from the (R)-stannane (R)-4.BF3-promoted additions give mainly or exclusively the syn adducts 49 and 51.Additions of (S)- and (R)-4 to (R)-3-(benzyloxy)-2-methylpropanal (61) yield the syn adducts 62 and 64 as major or exclusive products.
