Regulation of Diastereoselectivity in the Carbocyclization of Allenyl (<i>S</i>)‑<i>N</i>-<i>tert</i>-Butylsulfinimines through a Three-Component Assembly

Allenyl sulfinimines can be stereoselectively cyclized with hexamethylditin under palladium catalysis conditions followed by a selection of additives for an activated transmetalation. Reactivity and diastereoselectivity for the cyclization strongly depend on the characteristics of additives. A highly diastereoselective synthesis of five-membered rings is achieved from the reaction of the corresponding allenyl (<i>S</i>)-N-<i>tert</i>-butylsulfinimies through the following sequence. After the distannylation of the allenyl group with hexamethylditin catalyzed by the Pd complex, stereochemical routes are additive dependent: addition of SnCl₄ affords a <i>cis</i> ring exclusively, whereas a <i>trans</i> ring is formed predominantly by the introduction of <i>B</i>-bromocatecholborane. Extension of the methodology to the synthesis of six-membered <i>cis</i> rings is achieved by using <i>B</i>-bromocatecholborane. Stereochemical relationships of products were unambiguously deduced by X-ray crystallography

Asymmetric Aldol Reaction of Allenoates: Regulation for the Selective Formation of Isomeric Allenyl or Alkynyl Aldol Adduct

A highly stereoselective synthesis of 3-butynyl-<i>threo</i>-aldol adducts is achieved from the reaction of allyl allenoate with a chiral bromoborane in the presence of <i>i</i>Pr₂NEt, followed by addition of BF₃·OEt₂ as an additive to scavenge excess base and then aldehydes, whereas isomeric allenyl aldol adducts are formed in the absence of a Lewis acid additive from methyl allenoate

Mutations in <i>DZIP1</i> and <i>XYLT1</i> are associated with nonsyndromic early onset high myopia in the Korean population

Mutations in <i>DZIP1</i> and <i>XYLT1</i> are associated with nonsyndromic early onset high myopia in the Korean populatio